The x-intercept of the function f(x)=x^2-81

x=9

x=-9

Step-by-step explanation:

The x intercept or roots are x values that makes the f(x) equal 0. So in order words, to find the x intercept. Set the equation equal 0.

We can approach this problem 2 ways

Way 1: Differnece of Squares

Recall that

Since x^2 and 81 are both perfect squares and 81 is negative, we can say that

Set each equation to zero

Way 2: Take square root of both sides

Next step, take square root of both sides. Square root produce negative and positive solutions so

or

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step-by-step explanation: