Question

OMG can someone please help me solve this problem

Select the approximate values of x that are solutions to f(x) = 0, where
f(x) = -7x2 + 2x + 6.

A.){–0.79, 1.08}

B.){-7, 2}

C.) {–0.29, –0.86}

D.) {–1.17, 0.33}

Answer 1

The correct answer is A.) { - 0.79 ; 1.08 }, because
For ax^2 + bx + c = 0, the value of x is given by: ;
a = - 7 ; b = 2 ; c = 6 ;
b^2 - 4ac = 4 + 168 = 172 ;
`√(172)`≈ 13.11 ;
x 1 = ( - 2 + 13.11 ) / (- 14) = 11.11 / ( - 14 ) ≈ -0.79 ;
x = 2 = ( - 2 - 13.11 ) / ( - 14 ) = (-15.11) / (- 14 ) ≈ 1.08 ;