f(x)= 2x + x^2
The Attempt at a Solution
I don't know how to make x the subject
You need to solve for x in the equation x^2 + 2x = y. This is a simple quadratic equation.
No.Okay thank you!
I've got it:
X^2 +2x = y
add one so you get a quadratic that has a "squared"
x^2 +2x +1 = y + 1
(x+1)^2 = y + 1
x = (y+1)^-1/2 -1
Note that the equation y = x2 + 2x does not give y as a 1-to-1 function of x, so there is no inverse function, unless you place restrictions on the domain.f-1(x) = (x+1)^-1/2 -1