First problem:
Find the inverse of the function
m = 40 (d - 35)
Recall that for the inverse function we need to solve for d in terms of m (reverse the dependence), so we proceed to isolate d on the right hand side of the equation:
divide both sides by 40
m/40 = d - 35
now add 35 to both sides:
m/40 + 35 = d
The inverse function (dollars in terms of miles) is given then by:
d(m) = 1/40 m + 35
Second problem:
a = 7 * h / 2
in order to find the inverse function (as h in terms of a) we solve for h on the right hand side of the equation as shown below:
multiply both sides by 2:
2 * a = 7 * h
now divide both sides by 7 in order to isolate h on the right
2 a / 7 = h
So our inverse function of height in terms of area is given by:
h(a) = (2 a) / 7