solving two step equrtions

Ok so let's start by subtracting 15 from both sides.

so now its

-2x = -24

and now we divide both sides by -2

and now x = 12.

- 2x + 15 = - 9 | rearrange

15 - 2x = -9 | multiply -1

2x - 15 = 9 | + 15

2x = 24 | /2

x = 12