The function $\displaystyle {P}{\left({x}\right)}=-{1.25}{x}^{{2}}+{500}{x}-{4500}$ gives the profit when $\displaystyle {x}$ units of a certain product are sold. Find
a) the profit when 70 units are sold
Preview Question 6 Part 1 of 5   dollars
b) the average profit per unit when 70 units are sold
Preview Question 6 Part 2 of 5   dollars per unit
c) the rate that profit is changing when exactly 70 units are sold
Preview Question 6 Part 3 of 5   dollars per unit
d) the rate that profit changes on average when the number of units sold rises from 70 to 140.
Preview Question 6 Part 4 of 5   dollars per unit
e) The number of units sold when profit stops increasing and starts decreasing. (Round to the nearest whole number if necessary.)
Preview Question 6 Part 5 of 5   units