15. First Distribute
-6x-4 = 2X + 6
Add 6X on both sides
-4 = 8x+6
Subract 6 on both sides
8x=-10
Divide by 8 on both sides
X = -10/8 = -5/4
16. -13
17. Cross Multiplication
32 = 3X-3
Add 3 on both sides
35 = 3X
Divide by 3 on both sides
35/3 = X
18. Can't see the whole picture
19. Add 7 on both sides
6N = 42. Divide by 6
N = 7
20. 2x+6=-x+1. ---- I cross multiplied
2x+5=-x. ---- I subract 1 on both sides
-3x = 5. ----- Subract 2X
X=5/-3 ---- I divided it by -3
