Question

What does x equal in y=|x| when y=-3

Answer 1

Replace all the variables that we know the value for.

-3 = |x|

Make to equations from this one.

-3 = x and -3 = -(x)

Solve the first one.

-3 = x
x = -3 <-- Switch it around

-3 = -(x)
-(x) = -3 <-- Switch it around
x = 3 <-- Divide both sides by -1

So, there are two possible answers, -3 and 3.