Question

If f(x) and r1(x) are inverse functions of each other and f(x)=2x+5 , what is f^-1(8) ?

PLEASE HELP!!

Answer 1

3/2

Explanation:

Given y = 2x + 5, let's rewrite the equation in terms of x;

y = 2x + 5 => Bring 5 to the other side

2x = y - 5 => Divide either side by 2

x = (y - 5)/2

If we want to take the inverse, simply swap the variable's positions...

We have y = (x - 5)/2

Now let's determine f^-1(8), substituting for "y" provided y is our inverse, f^-1

f^-1(8) = (8 - 5)/2 = 3/2

Solution: 3/2