I think a) would be the answer. I proceeded by elimination: the domaine of the function goes from 3 and continues to infinity, so that leaves with a) and b) as possible answers. Both have the same range and both of their functions reflect over the x axis, so we have to compare the two answer by looking at the position of the function in the graph. The function is in the first quadrant (top right corner), so the position of the function has to be at our right, which leads us to a).
Answer: The inverse of the linear function f(x)=2x+1 is f^(-1) (x) = (1/2)x-1/2
Solution
f(x)=2x+1
y=f(x)
y=2x+1
Isolating x: Subtracting 1 both sides of the equation:
y-1=2x+1-1
y-1=2x
Multiplying both sides of the equation by 1/2:
(1/2)(y-1)=(1/2)2x
(1/2)y-1/2=x
x=(1/2)y-1/2
Changing "x" by "f^(-1) (x)" and "y" by "x":
f^(-1) (x) = (1/2)x-1/2
Y=x-2
..........................
.
one is (5) because Domain is left to right
and number two is (4) because range is up and down
