Question

Inverse of y = x2 + 12x.

Answer 1

y=2(x2−6x+m)

m=(b2)2

m=(−62)2

m=9

y=2(x2−6x+9−9)

y=2(x2−6x+9)−18

y=2(x−3)2−18

x=2(y−3)2−18

x+18=2(y−3)2

x+182=(y−3)2

±√12x+9=y−3

±√12x+9+3=y

Thus, ƒ−1(x)=±√12x+9+3. Don't forget the f−1(x) notation; I've been docked marks for this before.

Hopefully this helps!

Answer 2

To find the inverse, interchange the variables and solve for y.