How would I solve this​

When you answer this can you explain

Suppose that a households monthly water bill (in dollars) is a linear function of the amount of water the household uses (in hundreds of cubic feet, hcf). when graphed, the function gives a line with slope of 1.65. if the monthly cost for 13 hcf is $46.10 what is the monthly cost for 19 hcf?

If f(x) = -5x + 1 and g(x) = x3, what is (gºf)(0)? enter the correct answer