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

Question

asked Dec 12, 2023 89.5k views

2 Answers

Boris Churzin · Answer 1 · 2023-12-16T08:35:16+0000

Answer:

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

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.