how do i solve this problem?
Find the linear function f with x-intercept 6 and f -1 (-8) = -3.
i don't know how to do this at all.
Now use the given information, "with x-intercept 6" to get an equation with m and b in it. Call this equation (1).
Do you know anything about inverse functions? If so, then you should know that if (-8, -3) lies on the graph of $\displaystyle y = f^{-1}(x)$, then (-3, -8) lies on the graph of y = f(x). Use this to get another equation with m and b in it. call this equation (2).
Now solve equations (1) and (2) simultaneously for m and b.