'7. (13 pts) Solve the quadratic equation 2):2 x = 0 8. (13 pts) A store has been selling 210 at-screen TVs a week at $480 each. A market survey indicates that for each $20 rebate offered to buyers, the number of TVs sold will increase by 10 a week. How large of a rebate should the store offer to maximize its revenue? Hint: Revenue is price times quantity