First, I will explain it.
1. Multiply the #s inside the parenthesis Distributive Property.
It now looks like this: 5x-15-2x-2=4
2. Add like terms.
It now looks like this: 3x-17=4
3. Isolate the variable x.
It now looks like this: 3x=21
4. Now solve for x.
The answer is D, x=7.
(p.s. I won't give a stranger my number.)