select the approximate values of x that are solutions to f(x)=0 where f(x) = -4x^2+9x+5.

Question

select the approximate values of x that are solutions to f(x)=0 where f(x) = -4x^2+9x+5.

 

If you can also list the steps on how to get the result that would be really helpful as I am stuck and just can't seem to retain the steps or at least grasp the concept. 

Answer 1

Hi Anthony ..lets use the Quadradic formula...

 

X1,X2= (-b +-(sqrt(B^2-4*A*c))/(2*A))

 

A=-4

B=9

C=5

 

               X1=(-9+(Sqrt(9^2-4*(-4)*(5)))/(2*(-4))

 

               = (-9+(Sqrt(81+80))/-8))

 

           X1=(-9+-(Sqrt(161))

                  ________________

                            -8

 

             X1= (-9+12.69)                                          X2=(-9-12.69)

                    ___________                                             __________

                             -8                                                              -8

 

               X1=3.69                                                      X2= 0.46

                                            Pls check!.......Hope this helps

 

                     _____

                       -8

 

                 X1 = -0.46

 

 

 

Answer 2

Did you do a typing error for 9x???? Should it be 19x or8x?????