Let's assume y represent the earnings.
Given that, Henry receives a flat rate of $125 per day and can earn a $1.50 commission for each computer repair (r) he performs.
He earn $1.50 for one computer repair. So, her earning for r number of computer will be 1.50r.
So, we can set up an model for his earning as following:
y = 125 + 1.50 r
Yolanda receives a flat rate of $92 per day and can earn $7.75 per computer sale (s) she makes. Therefore,
y = 92 + 7.75 s
Hope this helps you!