Find the inverse of a quadratic. Find the inverse of the function y = x2 – 12.

Step-by-step explanation:

Please use " ^ " to indicate exponentiation:   y = x^2 – 12

1) Interchange x and y:  x = y^2 - 12

2) Solve this result for y:  y^2 = x + 12.  Taking the square root of both sides, we get y = ±√[x + 12].    

                                                               -1

3) Label this as the inverse function   f    (x) = +√[x + 12]

Note that if the inverse could take on two different values, then it is not a function.  It was for this reason that I eliminated the negative root.

Note that this inverse is valid only for [-12, infinity):  this is the domain

the equation for this situation is y=122+45. to solve the equation you would add 45 and 122 to get a total of 167lbs. in conclusion, grace's weight eight weeks ago was 167lbs.