Select the approximate values of x that are solutions to f(x)=0, where f(x)=-4x^2 +9x +9

Question

Multiple choice: a) -0.44, 1.00)  b) (-4, 9)  c) (-2.25, -2.25)  d) (-0.75, 3.00)

Answer 1

-4x² + 9x + 9 = 0

 

Use the quadratic formula:

 

x = (-b/2a) ± (1/2a)√(b²-4ac)

 

Where a = -4, b = 9, c = 9

 

x = 9/8 ± (-1/8)√(9²-4*(-4)(9))

 

x = 9/8 ± (1/8)√225

 

Can you finish it from here?