Question

Which of the following is an x intercept of the function f(x)=x^2-81?

Answer 1

Answer:

The correct option is C.

Step-by-step explanation:

The given function is

$f(x)=x^2-81$

Equate the given function equal to zero, to find the x-intercepts of the function.

$f(x)=0$

$x^2-81=0$

Add 81 both the sides.

$x^2=81$

Taking square root both the sides.

$x=\pm \sqrt{81}$

$x=\pm 9$

The x-intercepts of the given function are -9 and 9. Therefore the correct option is C.

Answer 2

x intercept when f(x) = 0
so
x^2-81 = 0
x^2 = 81
x = + 9 and x = -9

Answer
C -9