Consider the triangle ABC and its height AH show, you have m AC=60m, m AH=36cm and m BC =120 cm

1) a: [$]75 + [$]0.20x = ƒ(m) b: [$]0.35x = ƒ(m)the 75 is how much you automatically pay and the .2x and .35x is how much you would pay per mile (the variable can be changed to your liking). ƒ(m) is the total cost. 2) set your equations to equal each other.75 + .2x = .35xsolve.move the .2x over by subtracting it from both sides. 75 = .15xget x by itself by dividing both sides by 0.15.500 = xit would take 500 miles for plan a and b to be equal in cost.