Someone please help me I’ll give out brainliest please dont answer if you don’t know

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

Solve with work adding cheese to a mcdonalds quarter pounder increases the fat content from 21g to 30g. what is the percent of change ?

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