Find a linear function,f(x) =mx+bso thatf(1) = 2 andf(3) = 8

Question

Find a linear function,f(x) =mx+b so that f(1) = 2 and f(3) = 8

Answer 1

(1,2) (3,8) are two points on a line y=mx + b

m = slope = (8-2)/(3-1) = 6/2 = 3

y = 3x + b. to find b plug in either point

2 = 3(1) + b

b =2-3 = -1

y = 3x -1 is the line or linear equation through the points (1, f(x)) and (3, f(3)) = (1,2) and (3,8)