Question

Factor the polynomials completely, then solve. 4^2- 81 = 0​

Answer 1

Explanation:

4x^2 - 81 = 0

(2x - 9)(2x + 9) = 0

x = -9/2, 9/2

Answer 2

`x=\pm(9)/(2)`

Explanation:

I assume you mean
`4x^2-81=0`:

`4x^2-81=0\\(2x-9)(2x+9)=0\\x=(9)/(2),\:x=-(9)/(2)\\x=\pm(9)/(2)`

We were able to work quickly here since the original left-side expression was a difference of squares.