Question

Select the approximate values of x that are solutions to f(x) = 0, where
f(x) = -9x2 + 9x + 5.

(a){–1.80, 1.80}

(b){-9, 9}

(c){–1.00, –0.56}

(d){–0.40, 1.40}

Answer 1

it's 9x^2 not 9x2

Answer 2

so -9x^2 + 9x + 5 = 0

9x^2 - 9x - 5 = 0
Don't see any obvious facors, so let's use the formula

x (9 ± √261)/18
= appr 1.4 or -.4

looks like d)