Question

Select the approximate values of x that are solutions to f(x) = 0, where

f(x) = -2x2 + 2x + 6


answers available, which one is correct?

{–1.30, 2.30}

{-2, 2}

{–1.00, –3.00}

{–0.33, 0.33}

Answer 1

f(x) = -2(x^2-x) + 6
= -2(x^2 - x + 1/4) + 6 + 2(1/4)
= -2(x - 1/2)^2 + 13/2
f(x)=0 when

(x - 1/2)^2 = 13/4
x = (1±√13)/2
. . .