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 = 780 ... multiply by - 5

24x - 5y = - 3900 <===