Help with this math problem for my class

Which expression is equivalent to 8(k + m) − 15(2k + 5m)?

If 3x+8=3x+8 is it one solution or no solution

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?