Solve for x , and round answer to the thousandths place -4x^2 + 4x+9=0

x = 2.081, −1.081

Step-by-step explanation:

Use the quadratic formula to find the solutions.

−b±√b2−4(ac)

       2a

Substitute the values

a = −4, b = 4, and c = 9

into the quadratic formula and solve for x.

−4±√42−4⋅(−4⋅9)2⋅−4

Simplify the numerator.

Raise 4 to the power of 2.

x=−4±√16−4⋅(−4⋅9)

          2⋅−4

Multiply −4 by 9.

x=−4±√16−4⋅−36

       2⋅−4

Multiply −4 by −36.

x=−4±√16+144

       2⋅−4

Add 16 and 144.

x=−4±√160

  2⋅−4

Rewrite 160 as 4 to the power 2⋅10.

x=−4±√42⋅10

     2⋅−4

Pull terms out from under the radical.

x=−4±4√10

   2⋅−4

Multiply 2by −4.

x=−4±4√10

       −8

Simplify

−4±4√10

    −8.

         1 ± √10

x =  

             2

The result can be shown in multiple forms.

Exact Form:

       1±√10

x=

          2

Decimal Form:

x = 2.08113883…, −1.08113883…

ROUNDED:

x = 2.081, −1.081

answer: about 22.67

step-by-step explanation:

the answer is 99.