Question 762599
The only way where (x-3) can be equal to (3-x) is if x = 3.

How?
x - 3 = 3 - x

Add x to both sides, add 3 to both sides

x + x = 3 + 3

2*x = 6

x = 3

if x = 3, x - 3 = 3 - x = 0

:)