as a sales person at Trending Card Unlimited, Justin receives a monthly base pay plus commission on all that he sells. If he sells $400 worth of merchandise in one month, he is paid $500. If he sells $700 worth of merchandise in one month, he is paid $575. Find justin's salary if he sells $2500 worth of merchandise
We can use the 2-point form of the equation of a line to write a function that gives Justin's salary as a function of his sales.
We start with (sales, salary) = (400, 500) and (700, 575)
The 2-point form of the equation of a line is ...
y = (y2 -y1)/(x2 -x1)(x -x1) +y1
salary = (575 -500)/(700 -400)(sales -400) +500
salary = 75/300(sales -400) +500
For sales of 2500, this will be ...
salary = (1/4)(2500 -400) +500 = (2100/4) +500 = 1025
Justin's salary after selling $2500 in merchandise is $1025.