Which function below is the inverse of f(x) = x2 − 9?
f (x)=y
y=2x-9
X Y
-2 -15 y=2 (-2)-9
y=-4+-9
y=-15
-1 -11 y=2 (-1)-9
y=-2+-9
y=-11
0 -9 y=2 (0)-9
y=0+-9
y=-9
1 -7 y=2 (1)-9
y=2+-9
y=-1
2 -5 y=2 (2)-9
y=4+-9
y=-5
Here is all the work
Let f(x)=y
y=\(x^{2} -9\)
Make x the subject of the formula;
y+9=\(x^{2}\)
x=\(\sqrt{y+9}\)
So, the inverse of the function is thus;
\(f^{'} = \sqrt{x+9}\)