Question

Whats 7+3x=5x+13?????

Answer 1

$7+3x=5x+13\\ 7+3x-3x=5x+13-3x\\ 7=2x+13\\ 7-13=2x+13-13\\ -6=2x\\ \frac{-6}{2} =\frac{2x}{2}\\ -3=x$

Answer 2

7 + 3x = 13 + 5x

Add 5x to both side 

7 + 3x + -5x = 13 + 5x + -5x

This two is 0
5x + -5x = 0

Add seven on both sides
7 + -7 + -2x = 13 + -7

3 + -7 = 6

x = -3