Find an equation for the linear function which has f(150)=1500f(150)=1500 and f(650)=3900f(650)=3900

F(150) = 1500(150,1500)
f(650) = 3900(650,3900)

slope = (3900 - 1500) / (650 - 150) = 2400/500 = 24/5

y = mx + b
slope(m) = 24/5
(150,1500)...x = 150 and y = 1500
now sub and find b, the y int
1500 = 24/5(150) + b
1500 = 720 + b
1500 - 720 = b
780 = b
so ur equation is y = 24/5x + 780 or f(x) = 24/5x + 780 <==

or if u need it in standard form..
y = 24/5x + 780
-24/5x + y = 780multiply by -5
24x - 5y = - 3900 <===

Hope this ; )