Anyone knows the answer ??​

Acircle has a diameter will endpoints of (-2,8) and (6, 4). what is the center of the circle

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?

Use composition to determine if (x) or h(x) is the inverse of f(x) for the limited domain x2-1.