I need help with area of a polygon

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?

Answer pls man im trying to get out of summer school