Answer:
f = 2.5b
Step-by-step explanation:
The graph shows a straight line that passes through the origin, so this is direct variation.
The standard equation for direct variation is
y = kx,
where k is the constant of variation.
In this case, we have
f = kb
We need to find the value of k.
Read one point on the graph that is easy to read since it falls on a grid intersection. For example, look at (2, 5). Each point is of the form (b, f), so for point (2, 5), b = 2, and f = 5.
Replace b with 2 and f with 5 and solve for k in the equation f = kb.
f = kb
5 = k * 2
2k = 5
k = 5/2 = 2.5
Now replace k with 2.5.
f = 2.5b
The equation is f = 2.5b
