Answer:
6: m = 25 + 5x; m is the money made and x is the amount of chores done.
6b: m(4) = 25 + 5(4) = 25 + 20 = 45; m(4) = 45
7: c = 175 - 6x; c is the amount of cards Mason owns, x is the amount of months
7b: c(7) = 175 - 6(7) = 175 - 42 = 133; c(7) = 133
To make the equation, just find the starting value and then add in the amount of change that occurs in that number.