The 5’s cancel each other out, so you’re just left with a on that side, meaning -3=a.
Answer:
The Slope of a line formula is given by
m=y2 - y1/ x2 - x1
Now Form a triangle using the straight line(It'd be best if you choose known Points on the graph)
Picking points (1, 2) and (2, 5) connect these points and you'll have a small triangle.
x1 y1 x2 y2
Substituting into the formula
m=5-2/2-1
m=3.
You take 50/4 which equals 12.5
so now you say “well one sub is 2.95”
take that and multiply it by 12
12 x 2.95 = 35.4
then you take 2.95 and divide it by 2 that is 1.48
so now you take 35.4 + 1.48
the cost should be 36.88