Question

How do you solve for y in `9-y=1.5x`?

Answer 1

`9 = 1.5x + y`
`y = 9 - 1.5x`

OR

`-y = 1.5x - 9`
`-1(-y) = -1(1.5x - 9)`
`y = 9 - 1.5x`

Explanation:

There are two methods for rearranging this equation.

Term Transaction

1. Add `y` to both sides of the equation:
   `9 = 1.5x + y`
2. Subtract `1.5x` from both sides of the equation:
   `9 - 1.5x = y" or "y = 9 - 1.5x`

Notice that the variables have simply changed places and reversed their signs.

Multiply through by `-1`

1. Subtract 9 from both sides of the equation:
   `-y = 1.5x - 9`
2. Multiply both sides of the equation by `-1`:
   `-1(-y) = -1(1.5x - 9)`
   `y = -1.5x + 9" or "y = 9 - 1.5x`