Question

Given that f(x) = 9x2 − 180, find x

Answer 1

-162
Because 9 x 2 = 18
18 - 180 = -162

Answer 2

The values of x are
`x=√(20),\:x=-√(20)`.

Explanation:

We have the function
`f(x) = 9x^(2) - 180`.

To find the value of x, you must set the function to zero

`9x^2\:-\:180=0`

Next, add 180 to both sides

`9x^2-180+180=0+180`

Simplify

`9x^2=180`

Divide both sides by 9

`(9x^2)/(9)=(180)/(9)`

Simplify

`x^2=20`

`\mathrm{For\:}x^2=f\left(a\right)\mathrm{\:the\:solutions\:are\:}x=√(f\left(a\right)),\:\:-√(f\left(a\right))`

`x=√(20),\:x=-√(20)`.