Question

Solve this:

4x + 5x = 10(x - 2)

Please, answer ASAP as my sheet is due in 10 minutes.

Answer 1

$4x + 5x = 10(x - 2) \iff 9x = 10x -20 \iff -x=-20 \iff x=20$

Answer 2

4x + 5x = 10x - 20 
9x = 10x - 20 
-x = -20 
x = 20