approximate value of x where f(x) =-9x^2+6x+9

Question

Having problems completing this problem, not sure what to do at this point

Answer 1

Using the Quadratic Formula

 

x = [-6 ± √(36 + 324)] / -18

x = [-6 ± √360] / -18

x = [-6 ± 6√10] / -18

x = [1 ± √10] / 3