Question

if absolute value of x = absolute value of y

does that mean x = y?

Answer 1

it could also mean that x = -y

|x| = |y|

|-y| = |y| ... replace x with -y (since x = -y)

y = y ... which is TRUE

Answer 2

In general, if you have |x| = k, where k is some positive number, then

x = k or x = -k

Answer 3

I'm looking to write y in terms of x or x in terms of y, what to do?

Answer 4

you can say

y = x

or

y = -x

Answer 5

or you can say

x = y

or

x = -y