LINEAR EQUATIONS -FACT SHEET 

What the equation looks like:

Standard form (be able to rearrange to Slope-Intercept Form):
AX + BY + C = 0, where A, B, C are integers, A is positive

Slope-Intercept Form:
y = mx + b (be able to rearrange to Standard Form):
where m is slope, expressed in a/b form, a and b are integers, b is not 0

What makes it linear:
the equation–the exponent of both X and Y is 1
the graph is a  a straight line

SLOPE FORMULA:	

To find the equation of a line:
(I)	Given 2 points, first use the slope formula to find slope
	Then substitute the slope and one of the points into y = mx +b to find
	b and then state the equation in y = mx + b form

(II) Given the slope and one point substitute these into y = mx +b to find
	b and then state the equation in y = mx + b form

Parallel lines have the same slope

Perpendicular lines have slopes which are negative reciprocals to each other (e.g., 5 and -1/5).

Direct variation: b = 0 so the line passes through the origin

Partial variation: b does not equal 0 so the lines does not pass through the origin

Y-Intercept: the point where a lines passes through the Y-axis.  This point has the form (0, Y)

X-Intercept: the point where a lines passes through the X-axis.  This point has the form (X, 0 )