We want to get the variable by itself, but what we do to one side we have to do to the other. So for the first one, adding 8 to both sides gives 4x-8+8=32+8 which simplifies to 4x=40. Next, to isolate x we divide both sides by 4 giving x=10
For the second one, we have 2(x-5)=-20. We can divide both sides by 2, giving x-5=-10. Then by adding 5 to both sides, we get x=-5