Question

Let f(x) = x2 - 81. Find f-1(x).

Question 7 options:
1) ± √x+81
2) ± 9√x
3) 1 over x^2-81
4) x^2 over 81

Answer 1

1)

http://www.wolframalpha.com/input/?i=+f%28x%29+%3D+x2+-+81%2C+inverse

Answer 2

Let f(x) = 5x + 12. Find f-1(x).

Question 6 options:
1) 12x + 5
2) 1 over 5x+12
3) 5 over x-12
4) x-12 over 5

Answer 3

4
http://www.wolframalpha.com/input/?i=+f%28x%29+%3D+5x%2B12%2C+inverse