How many slices do we slice our pie into if we see the fraction 12/13

And employee salary increased by $4500 which represents a 15% raise what is the rate of the increase

Acar dealership pays you 5% commission on your first $10,000 on car sales and 8% commission on the sale amount over $10,000 if you sold a $12,000 car how much is your commission

Determine which expressions represent real numbers and which expressions represent complex number. asaaap! plis!