For a linear function f, the graph of y = f (x) in the xy-plane passes through the points (4, 22) and (7, 37). Which equation defines f?

The correct answer is: f(x) = 5x + 2

Clearly as x increases y increases as well so it must have a positive slope. Eliminate C & D.
Substituting x = 4 in option B. we get y = 42
Which does not represent points given above.
Eliminate B. we are left with A as the answer.