Over what part of the domain is function f decreasing?

If jm equals 5x -8 and lm equals 2x -6 which expression represents jl

Alana has 12.5 cups of flour with which she is baking four loaves of raisin bread and one large pretzel. the pretzel requires 2.5 cups of flour to make. how much flour is in each loaf of raisin bread? explain the steps to follow to get the answer.

Idon’t understand! use slope intercept form to solve: through: (2,5) slope= undefined