f(250) = 1400......this means (250,1400)....x = 250 and y = 1400
f(750) = 3600......this means (750,3600)....x = 750 and y = 3600
now we find the slope by using the slope formula and our points.
slope = (y2 - y1) / (x2 - x1)
(250,1400)....x1 = 250 and y1 = 1400
(750,3600)....x2 = 750 and y2 = 3600
now we sub
slope = (3600 - 1400) / (750 - 250) = 2200 / 500 = 22/5
now we use y = mx + b
slope(m) = 22/5
u can use either of ur points....(250,1400)...x = 250 and y = 1400
now sub into the formula and find b, the y int
1400 = 22/5(250) + b
1400 = 1100 + b
1400 - 1100 = b
300 = b
so ur equation would be : y = 22/5x + 300 or f(x) = 22/5x + 300
