Value of x

Question

Select the approximate values of x that are solutions to f(x) = 0, where
f(x) = -2x2 + 2x + 6.

{–1.30, 2.30}

{-2, 2}

{–1.00, –3.00}

{–0.33, 0.33}

Answer 1

In other words solve quadratic equation

 

-2x² + 2x + 6 = 0

 

Use solution of standard quadratic equation ; ax² + bx + c = 0

 

 x = (-b + √(b² - 4ac))/2a

 

here a = -2 , b = 2, c=6

 

x = (-2 + √(52))/-4 = (-2 + √52)-4

 

x = (-2 + 7.2)/-4

 

x = 2.35 or -1.3

 

So option #1 is correct

:)