Multiply the first equation by -2. This gives you a positive and a negative 8b, which can cancel out, leaving you with -16a = -40 and 5a = 62, which can be added together to make -11a = 22. Divide 22 by -11 to get a alone. A then equals -2. Plug -2 in for a in either equation. Solve for b, giving you -9. Plug these in again just to check if you'd like.
So, as a quick recap, just a is -2 and b is -9. Hope I helped!
