Rational Expressions and Equations
posted by April .
How do you know when to move the number to the left or the right.
For example
(x5)/(x+8)=5/7 or
(y2)/(y+2)=3/7

What are you trying to do? Solve for the unknown (x or y?)
First get rid of the fractions that have the unknowns in the denomimator. It is not a question of moving right or left.
In the first case,
7(x5) = 5(x+8)
7x 35 = 5x + 40
2x = 75
x = 37.5 
I know the first problems answer is 2/75 and the second is 5 and in both cases I seem to mess up on the last part of moving the numbers like for instance in the 2/75 I first had the answer of 75/2 I had the numbers right but the wrong placement and the same with the other I first had 4/20 instead of 20/4 which equals 5 so I need to know how do you know which way to move the number to the left or the right?