
John B. answered 08/23/19
Pre-calculus
I drew a plot of this piecewise function, but it was too much data and was not allowed for an answer. So I will try to describe it the best I can here.
For 0 units, there is no price per unit, so the graph would start at U = 1 for 1 Unit. Suppose that 1 Unit results in a Price / Unit of $A. Also suppose that the graph would be linear between U = 1 and U = 10.
P (1) = $A
P (10) = $21
Taking the slope of these two points, the plot between 1 and 10 would have a slope of
( $A - $21 ) / (1 - 10) = $29 / -9 = -($21 - A) / - 9 = ($21 - $A) / 9
Price / Unit = P
(($21 - $A) / 9)*U + $A for 1 <= U < 10
P =
$21 for U > 10