how do you solve 70= -7 (-2-2z)?

First you need to get rid of the ( ) so you multiply the numbers inside the ( ) by -7, so you now have 14 +14Z. Now move the 14 to the other side of the equal sign by subtracting both sides by 14. Now you have 14Z = 56 so finally divide both sides by 14 to get Z = 4.

It looks like this:
70 = -7(-2-2Z)
70 = -7 * -2 + -7 * -2Z
70 = 14 + 14Z
70 - 14 = 14 - 14 + 14Z
56 = 14Z
56 / 14 = 14Z / 14
Z = 4