values of x

Question

select the approximate values of x that are solutions to f(x)=0, where f(x)= -5x^2+5x+9

 

A). {1.93, -0.93}

 

B) {-5, 5}

 

C) {-1.00, -1.80}

 

D) {-0.56, 0.56}

Answer 1

use the quadratic formula

 

(-5+√25+180)/(-10)

(-5+√205)/(-10)

(-5+14.3178)/(-10)

-19.3178/-10=1.93

9.3178/-10=-0.93

A. is the answer