TRENTON HIGH SCHOOL Algebra 1a and 1 b Notes


SCOPE OF ALGEBRA 1 A Mr. David Kotait THS Building 21

THE FOLLOWING NOTES WERE DONATED BY SEVERAL ALGEBRA 1 STUDENTS

Ch. 1, Sec. 1

Notes � Variables are letters that stand in place of an unknown number. � Equations always have an equal sign. � More means to add. Less means to subtract. Product means to multiply. Quotient means to divide.

Ch.1, Sec.2

Notes � An exponent is a number that tells how many times to multiply the base by itself. � Simplify means to solve, reduce, or put in simplest form. � X to the second power is the same as X times X, or X^2 or X squared. � P: Parenthesis E: Exponent M: Multiply D: Divide A: Add S: Subtract

Ch.1, Sec.3

Notes � Natural Numbers: 1,2,3,  N � Whole Numbers: 0,1,2,3,  N � Integers: N, 2, 1, 0, 1, 2  N � Rational Numbers: A/B where B is not equal to Zero. � Terminating Decimals are decimals that end. � Repeating Decimals are decimals that repeat and go on forever. � Rational Numbers are numbers that either terminate or repeat. � Irrational numbers are numbers that go on forever, but don�t repeat. � A counterexample is an example that proves a statement false. � Equalities have an equal sign. � Inequalities have either a  symbol or a  symbol. � When ordering fractions, the larger the denominator, the smaller the value of the fraction. � When dividing fractions, you multiply by the reciprocal. � The absolute value of a number is its distance from zero on a number line.

Ch.1, Sec. 4

Notes When multiplying/dividing positive and negative numbers: � If both numbers are positive, then the answer is positive � If both numbers are negative, then the answer is negative. � If the signs are different, then the answer is negative. � Evaluate means to substitute a variable. +1 + 1  2 -1 + 1  0 -1 � 1  -2 +1 � 1  0

Ch.1, Sec.6

Notes � Identity property: Anything multiplied or divided by 1 is equal to itself. � Zero Property: Anything multiplied or divided by 0 is equal to zero. � Anything multiplied by �1 is equal to that numbers opposite. � When multiplying numbers with the same sign, the answer will always be positive. � When multiplying numbers with different signs, the answer will always be negative. � Inverse property: Anything multiplied by its multiplicative inverse is equal to one.

Ch.1, Sec.7

Notes The Distributive Property 4(a+b)  4a+4b 3(2x+5) = 6x +15 x(2x+3) = 2x+3x = 5x

Ch.1, Sec. 8

Notes � Commutative Property of Addition/Multiplication: You can switch the order in which you add/multiply the integers, without changing the sum/product. 3+7 is the same as 7+3 � Associative Property of Addition/Multiplication: You can change the grouping of the integers without changing the sum/product. (2x3) X 5 is the same as 2(3x5) � Identity Property of: Addition-anything added to zero is equal to itself. Multiplication-anything multiplied by 1 is equal to itself. � Inverse Property of: Addition- anything added to its opposite is equal to zero. Multiplication-anything multiplied by its inverse is equal to 1. � Multiplication Property of �1 N x �1 = -N

Ch.1, Sec.9

Notes (2, 3) II I III IV An ordered pair shows something�s location on a coordinate plane. Each of the 4 sections is called a quadrant.

Ch.2, Sec. 1

Notes 3 + X =10 -3 -3 X =7 -1 + 3 + X �2X = 10 -1 + 3 � X = 10 2 - X = 10 -2 -2 -X = 8 x �1 x -1 X= -8 Always write work out to the side.

Ch.2, Sec.2

2x - 12= 4 given +12 +12 + 12 to both sides 2x = 16 simplify 2 2 divide both sides by 2 X = 8

Ch. 2, Sec.3

2c+c+12=78 3c+12=78 -12 -12 3c=78 3 3 C=26

Ch.2, Sec.4

2x+3=2+x To solve this, you must get X�s on one side and the integers on the other. -x -x x+3=2 -3 -3 x = -1

Ch.2, Sec.5

Jacksonville to Daytona = X Jacksonville to Gainesville=D X + D = the distance from Gainesville to Daytona Consecutive Integers are integers that are in numerical order. 1,2,3 To find consecutive integers: X + X+1 + X+2 3X + 3 Distance equals rate times time D = R x T To find same direction travel: 1. Set up the equations and set them as equal. 2. Solve, subtract beginning time, etc. To find round trip distances: 1. Set up the equations, set them as equal 2. Solve

Chapter 3-1

Inequalities and their Graphs x<5 2<5 so x can = 2 0 = just lower or greater than . = equal to and lower or greater than Solution of an inequality - any number that makes the inequality true.

Chapter 3-2

Solving Inequalities Using Additional and Subtraction x-3 >5 +3 +3 x>8 x+3 >5 -3 -3 x>2 Equivalent Inequalities- are inequalities with the same solutions.

Chapter 3-3

Solving Inequalities using multiplication and Division x 2 < -1 .2 .2 x<-2 -2x + 3+x > 6 -x + 3 > 6 -3 -3 -x > 3 .-1 .-1 x <-3

Chapter 3-4

Solving Multi- Step Inequalities 7 + 6a =9 -7 -7 6a = 2 6 6 a = .3333 7 + 6a > 9 -7 -7 6a > 2 6 6 a > .3333 -3(4-m) > 4(2m + 1) -12 + 3m > 8m + 4 +12 +12 3m > 8m + 16 -8m -8m -5m > 16 -5 -5 m > -3 1/5

Chapter 3-5

Compound Inequalities Less than = and greater than or for and -3 < j +2 < 7 -5 3 or 6k < -3 k > 3 or k < -5 Compound Inequality - two inequalities that are joined by the word and or the word or.

Chapter 3-6

Absolute Value Equations and Inequalities [x] = 2 [x] + 5 = 11 [x] = 6 x = 6 or -6 and = greater than > or = less than <

Chapter 4-1

Ratio and Proportion 20 Girls 6 Boys girls boys 20:6 Unit Rate: 10 pcs. $75 10 = $7.50 a/b = c/d means - extreme ad = bc cross multiplication t/9 = 5/6 6t = 45 t = 7.5 Proportion - an equation that states that two ratios are equal. Extremes of the proportion - for the equation a/b = c/d and d are the extremes. Means of the proportion - for the same equation b and c are the means. Cross products - are the ones you cross in and multiply. for a/b == c/d ad and bc are cross products.

Chapter 4-2

Proportions and Similar Figures Corresponding sides: are having the ratio or proportion and there are 2 equal angles. (~)Means they are similar 2500sq ft With two sides 50ft The scale is 10' to 1" Similar figures-the same shape but not necessarily the same size. Scale drawing-an enlarged or reduced drawing that is similar to an actual object or place. Scale-ratio of a distance in the drawing to the corresponding actual distance.

Chapter 4-3

Proportions and Percent Equations n or x x or n x or n % What percent of 80 is 18?� N = 18 100 80 80n=1800 n=22.5 CENTER>

ADDITIONAL:

Chapter 3 Notes 3-1

Inequalities and their Graphs x<5 2<5 so x can = 2 <-------------0 <--------------------------------5---> 0 = just lower or greater than . = equal to and lower or greater than Solution of an inequality - any number that makes the inequality true.

3-2

Solving Inequalities Using Addition and Subtraction x-3 >5 +3 +3 x>8 x+3 >5 -3 -3 x>2 Equivalent Inequalities- are inequalities with the same solutions.

3-3

Solving Inequalities using multiplication and Division x 2 < -1 .2 .2 x<-2 -2x + 3+x > 6 -x + 3 > 6 -3 -3 -x > 3 .-1 .-1 x <-3

3-4

Solving Multi- Step Inequalities 7 + 6a =9 -7 -7 6a = 2 6 6 a = .3333 7 + 6a > 9 -7 -7 6a > 2 6 6 a > .3333 -3(4-m) > 4(2m + 1) -12 + 3m > 8m + 4 +12 +12 3m > 8m + 16 -8m -8m -5m > 16 -5 -5 m > -3 1/5

3-5

Compound Inequalities Less than = and Greater than or For and -3 < j +2 < 7 -5 For Or 4 + k > 3 or 6k < -3 k > 3 or k < -5 <--0 0----> <--(-5)------------(-1)-------------------------------> Compound Inequality - two inequalities that are joined by the word and or the word or. 3-6 Absolute Value Equations and Inequalities [x] = 2 0-------0---------0 -------(-2)------0--------2----------- [x] + 5 = 11 [x] = 6 x = 6 or -6 [-------------------------------------] ------(-6)-----------------------------------6-------- and = greater than > or = less than <

Chapter 4 Notes

4-1

Ratio and Proportion girls boys 20 6 20:6 girls ratio is 26 girls boys 20 6 26 26 Unit rate 10 pcs. $75 75 10 = $7.50 a/b = c/d Means - extreme ad = bc Cross multiplication t/9 = 5/6 6t = 45 t = 7.5 Proportion - an equation that states that two ratios are equal. Extremes of the proportion - for the equation a/b = c/d and d are the extremes. Means of the proportion - for the same equation b and c are the means. Cross products - are the ones you cross in and multiply. For a/b == c/d ad and bc are cross products.

4-2

Proportions and Similar Figures Corresponding sides: are having the ration or proportion and there are 2 equal angles . . . Means they are similar 2500sq ft with two sides 50ft The scale is 10' to 1" Similar figures - the same shape but not necessarily the same size. Scale drawing - an enlarged or reduced drawing that is similar to an actual object or place. Scale - ration of a distance into he drawing to the corresponding actual distance.

4-3

Proportions and Percent Equations n or x x or n x or n % 100 25 75 100 = 25% 320 = 23% 80 is 25% of what number 25 80 100 x

x = 320 4-4

Percent of Change % triangle = change New - old old If the New is bigger than old = Increase If the Old is bigger than New = Decrease 16 16.70 1 x 1/2 = .5 = percent error .10 x 1/2 = .05 = percent error 16.75 x 1/2 = .005 = percent error Percent of Change - the ration amount of change over original amount experessed as a percent. Percent of Increase - when a value increase from its original amount. Percent of Decrease - when a value decreases from its original amount. Greatest Possible Error - in a measurement is one half of that measuring unit. Percent Error - greatest possible error over measurement.

4-5

Applying Ratios to Probability Probability - possibility Outcome - end result Event - activity Theoretical probability - # of favorable outcome over # of possible outcome 6 1 24 = 2 Experimental probability? 1000 skateboards 992 are good 992 1000 are good 99.2% are good .008% is bad Probability - tells you how likely it is that something will occur. Outcome - the result of a single trial. Event - any outcome of group of outcomes. Sample Space - is all of the possible outcomes. Theoretical probability - # of favorable outcome over # of possible outcome. Complement of an event - consists of all the outcomes not in the event. Experimental probability - number of times an event occurs over number of times the experiment is done.

4-6

Probability of Compound Events Compounded: more than one time Independent: 1B 2x 20 20 100 100 1 1 1 5 x 5 = 25 Dependent: 1 1 1 5 99 = 495

Chapter 5

5-1

Relating Graphs

5-2

Relations and Functions The first numbers in an ordered pair are the domains the second numbers are the ranges once put in ruder. Domain - Independent/ x axis Range - dependent/ y axis function: for every value of "x" you have a unique and only one value of "y". Vertical Line test: It's not a function if theres more than one point on one vertical line. y = mx +b m= slope b = "y" intercept f(x) = mx+b means it's already a function. Relation - a set of ordered pairs. Domain - a relation is the set of first coordinates in an ordered pair. Range - the set of second coordinate in an ordered pair. Function - a relation that assigns exactly one value in the range to each value in domains. Vertical line test - a way to analyze the graph of the relation. Function Rule - an equation that describes a function. Function Notation - when you use f(x) to indicate the outputs.

5-3

Function Rules, Tables, and Graphs Xs = Domain, Independent variables Ys = Range, dependent variables For every x there is only on unique value of Y. y=mx+b Slope = rise over run = y2 - y1 over x2 -x1 b = y intercept (where the line intersects the y axis) y = .5x +3 To find the "y" intercept set x = 0 To find the 'x' intercept set y =0 y = .5x + 3 Set y = 0 0 = .5x + 3 x = -6 Absolute Value: Do the same as any other just follow absolute value rules. Independent variable - inputs are values. Dependent variable - outputs are the corresponding values.

5-4

Writing a Function Rule y = mx +b f(x) means it's a proven function 1) Graph the data 2) Find out where does it the "y" intercepts 3) Find the slope rise over run 4) Must take 2 consecutive points

5-5

Direct Variation y = kx y = mx It is not a direct variation y = k x k = coefficient of x Constant of variation (x,y) (2,3) write an equation with the constant of variation y = kx 3 = k2 Divide both by 2 k = 3/2 y = 3/2x Direct variation - function in the form y = kx, where k doesn't equal 0. Constant of variation - k is the coefficient of x.

5-6

Describing Number Patterns A(n) = a + (n - 1)(d) a = First term n = term number d = difference in the terms Example A(n) = -9 + (n - 1)(6) find for fifth term -9 + (5 - 1)(6) -9 + (4)(6) -9 + 24 = 15 Inductive Reasoning - making conclusions based on patterns you observe. Conjecture - conclusion you reach by inductive reasoning. Sequence - number pattern. Term - each number in a sequence. Arithmetic sequence - adding a fixed number to each previous term. Common difference - fixed number. 1

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