In number 5 it asks what is the constant of varuation. what does that mean

The constant of variation is basically a unit rate in a proportional relationship.

For example, 1 apple equals $3.00

So, the x would be the amount of apples since it's a quantity or term. And y would be the money.

So you could write the proportional relationship like this y = kx

k stands for the constant of variation. So in this example, it would be like this y = 3.00x

So let's say Milly buys 3 apples, we could write that proportional relationship like this y = 3.00(3) which means that y = 9.00 Since Milly bought 3 apples

I know this was not the best explanation. But I hope that you got a better understanding of what constant of variation means ^^