Question

45 + 35n = 45 + 40n what is n?

Answer 1

subtract both sides from 45 
45+35n-45=45+40n-45
35n=40n
n=0

Answer 2

Subtract 45 on both sides

35n = 40n

Divide n on both sides

35 = 40

This is obviously false, which means that this equation has no solution.

But wait! n = 0 is a solution.

35(0) = 40(0)
0 = 0