Sergey is solving 5x2 20x â€"" 7 = 0. which steps could he use to solve the quadratic equation by completing the square? select three options. 5(x2 4x 4) = â€""7 20 x 2 = plus or minus startroot startfraction 27 over 5 endfraction endroot 5(x2 4x) = 7 5(x2 4x 4) = 7 20 5(x2 4x) = â€""7