help me solve these

5. [-/7.69 Points] DETAILS HUNTERDM3 2.2.016. MY NOTES Write down all elements of {F, G, H} x {R, S). (Enter your answer in set notation.) 6. [-/7.69 Points] DETAILS HUNTERDM3 2.2.021. MY NOTES List all of the elements SE P({1, 5, 7, 8}) such that |S| = 3. (Enter your answer as a set of sets. ) 7. [-/7.69 Points] DETAILS HUNTERDM3 2.3.014A. MY NOTES Define a function f : R - R by the formula f(x) = 4x - 8. Prove that f is one-to-one. Let a, b E R, and suppose that f(a) = f(b). Then 4a - 8 = so a =