standard_description: Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in the coordinate plane; derive the equation y = mx for a line through the origin and the equation y = mx + b for a line intercepting the vertical axis at b.
problem_activity: The function,
$$f$$
, defines the cost of supplies for a lemonade stand as a function of the number of cups of lemonade you expect to sell.
$$f(x) = .5x + 10$$
Write
$$f^{-1}$$
algebraically and define the domain and range for both
$$f$$
and
$$f^{-1}$$
in the context of the problem.


aligns: no