81-4x^2

please explain how you got your answer

Step-by-step explanation:

81 - 4

         notice how this is difference of squares, meaning you can simplify

(9-2x) (9+2x)

         if the question is asking to find roots, then you just set this equal to 0, and that means that either 9-2x or 9+2x must be equal to 0.

9-2x = 0                    9+2x = 0

9 = 2x                       9 = -2x

x = 4.5                      x = -4.5

Therefore the two roots of this equation are ±4.5

1) 2/5

2) zero=0/1

3) zero=0/2

4) -4/5

5) undefined=3/0