Regardless of his sales, Dom earns $285 per week.
He also earns 8% on all his sales, that is, 0.08($4213) = $337.04.
Add these two amounts together to obtain Dom's total income for this week.
Note that this is a linear equation. If E = earnings for the week, then
E = $285 + 0.08($4213). Looks like E=salary + commission.