Let us find the value of x
[tex]f(x)=x^2-1[/tex]Since f(x) = 99, so substitute f(x) by 99 in the formula above
[tex]99=x^2-1[/tex]To solve the equation add 1 to both sides
[tex]99+1=x^2-1+1[/tex][tex]100=x^2[/tex]To get x take a square root for both sides
[tex]\pm\sqrt{100}\text{ = x}[/tex]So the values of x are -10 , 10
For the square root there are to values one of them positive and the other is negative because -10 * -10 = 100 and
