Select the approximate values of x that are solutions to f(x) = 0, where f(x) = -4x2 + 3x + 5.

Question

Select the approximate values of x that are solutions to f(x) = 0, where
f(x) = -4x2 + 3x + 5.

Answer 1

For -4x^2+3x+5=0, I would use the quadratic formula to solve for x.

 

x=(-3±√(3^2-4(-4)(5)))/(2*-4)=(-3±√(9+80))/-8=(-3±√89)/-8

 

Hence, x=(3-√89)/8 ≈-0.804 or x=(3+√89)/8 ≈ 1.55

 

Hope this helps.