Answer:
f(x) = 7.5x
Explanation:
you can find the slope by using the slope formula (y2-y1)/(x2-x1). you can use any of the values but for this example I'll be using (2, 15) and (4, 30).
(30-15)/(4-2) = 15/2 = 7.5.
now we can use one of the coordinates to find the y-intercept by plugging the known values in the equation y=mx+b where m is the slope and b is the y-intercept.
for this example I'll be using (2, 15) but you could use any of the values you gave.
15 = 7.5(2) + b
15 = 15 + b
0 = b
so now we have the function rule
f(x) = 7.5x + 0 or just f(x) = 7.5x