Hello,
And you want y with respect to x.
Solve this quadratic equation, treating x as a constant.
Be aware that the range of x is particular, because if the discriminant is negative, there is no real solution.
f(x) = x^2 - 8x
find f^-1 (x)
i know this must be very simple but i have no idea what to do here. can somebody just show me how it is done? i am really at a loss of what to do, especially since i usually have no problem with inverse functions. i just use f(x)= y and solve for x, then replace y with x.
A very good thing to have said initially because the function you gave does not have an inverse! Solving the equation y= f(x) for x gives two different solutions depending on whether you take the positive or negative square root. But those two solutions "meet" at x= 4. That is, one sign gives x>4, the other <4.