Question 1018543
So, we are trying to create a formula for y (earnings). It looks like Mark gets income from 2 different sources. An hourly wage for $18 an hour and some percentage of his sales. His total earnings will be the sum of these two things

When we say that someone makes $X an hour, that means we should multiply that many dollars by how many hours they worked to get the total amount of money they made

Example: If I work 4 hours at $18 an hour, I made 4*18 = 72 dollars.

So money that he earned from his hourly wage is 18*h

The problem also says that he makes 5% commission. That means he earns 5% of what ever he sold. Another way to think of percent is "how many out of a hundred", so for every $100 worth of stuff he sold, he earns $5

5% when written as a normal number is 0.05 (you could also write this as 1/20 and we can multiply that by the amount of stuff he sold to get his earnings for his commission .05 * s

The sum of these two should give you your answer.