Answer:
[tex]\displaystyle f(x) = -\frac{11}{4}(x + 1) + 2[/tex]
Step-by-step explanation:
We want to find the linear function given that:
[tex]f^{-1}(2) = -1\text{ and } f^{-1} (-9) = 3[/tex]
Recall that by the definition of inverse functions:
[tex]\displaystyle \text{If } f(a) = b\text{ then } f^{-1}(b) = a[/tex]
In other words, f(-1) = 2 and f(3) = -9.
This yields two points: (-1, 2) and (3, -9).
Find the slope of the linear function:
[tex]\displaystyle m = \frac{\Delta y}{\Delta x} = \frac{(-9) - (2)}{(3) -(-1)} = -\frac{11}{4}[/tex]
From point-slope form:
[tex]\displaystyle y - (2) = -\frac{11}{4}( x- (-1))[/tex]
Hence:
[tex]\displaystyle f(x) = -\frac{11}{4}(x + 1) + 2[/tex]
We can simplify if desired:
[tex]\displaystyle f(x) = -\frac{11}{4}x -\frac{3}{4}[/tex]
