Question

Algebra help please! :)

Answer 1

As a sales person at Scrapbooks and Treasures, Alysse receives a monthly base pay plus commission on all that she sells. If she sells $600 worth of merchandise in one month, she is paid $320. If she sells $900 of merchandise in one month, she is paid $380.

Find Alysee's total salary function, s(x), when she sells x dollars of merchandise.
s(x) = _____________

Answer 2

The correct answer was 0.2x + 200...
It says "Use the information in the problem to write a system of equations given then amount of merchandise sold and the total salary.
320 = 600a + b
380 = 900a + b
Then, solve the system for a and b.
-320 = -600a + b
60 = 300a
a = 0.2
320 = 600 * 0.2 + b
320 = 120 + b
b = 200
So, this is the total salary function:
s(x) = 0.2x + 200"

How do you get the 0.2x 200? Im lost there..