I need help on math because my teacher won't help me

What is the point-slope form of the equation for the line with a slope of -2 that passes through (1,4)?

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?

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?