Suppose a one-year subscription to a magazine costs $12.99 and a three-year subscription costs $25.98. The cost and length of a subscription are related. Write a slope-intercept equation to model the cost of a subscription for any period of time.

Step-by-step explanation:

Represent years with x and cost with y.

So, we have:

Required

Determine the slope intercept equation

First, we calculate the slope (m)

The equation is then calculated as:

Where

Make y the subject

y=3x+4

step-by-step explanation:

given the points a(0,4) and b(-4, -8)

eqn of line ab: (y-4)/(x-0)=(-8-4)/(-4-0)

(y-4)/x=-12/-4=3

y=3x+4