Question

81-4x^2

please explain how you got your answer

Answer 1

Explanation:

81 - 4
`x^(2)`

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

Answer 2

b = 2 x .

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

Explanation:

Since both terms are perfect squares, factor using the difference of squares formula, a 2 − b 2 = ( a + b ) ( a − b )