Christina M.
Algebra 2 .1st
Chapter 9 :Exploring rational expressions (Glencoe edition) section 9.2 - Direct ,Inverse and Joint variation
Direct variation equation- y1/ x1 = y2 / x2 (y1=kx2 and y2=kx2)
example 1 : If y varies directly as x and y = 2 when x is 2 find y when x=8
- first step is to set the problem up using the direct variation equation 2/2 = y/8 ,next you must cross multiply 2(y)=2(8)
2y=16 therefore x= 8
Inverse variation equation - y1/x2=y2/x2
example 1 : if y varies as x and y=6 when x =8 find y when x=2
- The first step in solving this problem is to set up the number using the inverse equation. 12/y2=2/6 next cross multiply and 2y=72 divide each side by 2 and you get 36 for y
Joint variation equation - y=kxz
example 1: if y varies as x and z find y when x=2 ,y=4 and z=6 and y=14
next set up the problem to solve . y= (4)(2)(6), so 14=(4)(2)(6) 14=28
divide 14 by 28 and you get the answer is 2..
If apples vary directly to oranges and apples =4 and oranges =12 find apples when oranges =8 .solve 4/12=y/8= 4y=96 and your final answer is 24 apples.
if you got the answer 24 then you are well on your way to doing a great job with this section .
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Character QUOTE -" every champion began as a novice someone believed in. will you give up ,or give yourself a chance to improve . this is perseverance and it means that you control what you do if you don't try hard and believe in yourself no one else will so it's up to you to persevere. "
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