How do you solve -4y - 15= 8y + 9?

1 Answer
Jun 22, 2017

y=-2

Explanation:

When solving one-variable equations, the goal is to isolate that variable.

-4y-15=8y+9

The first step is to put all y terms on one side of the equation, and all constants on the other side.

Subtract 8y on both sides.

-12y-15=9

Then, add 15 on both sides.

-12y=24

Last, you divide -12 on both sides to completely isolate y.

y=-2

In summary, to isolate variables you just have to perform the inverse of operations until the variable is completely on its own.