Question

How do you solve `\frac { y + 9} { y - 12} = \frac { - 3} { y - 12}`?

Answer 1

`y = -12`

Explanation:

First, multiply both sides by `y-12`. Note that `y` cannot be 12, since this would result in dividing by `0`. This gives us:

`y + 9 = -3, color(white)"X" y != 12`

Now subtract `9` from both sides.

`y = -12, color(white)"X" y != 12`

So the solution is `y = -12`. The `y != 12` part doesn't matter, since `y=12` wouldn't have been a solution anyway.