Question

Form linear functions given the following information:

f(1)=−2 and if f(x)=0 , then x=4

Answer 1

let the function be y = mx + b
when x = 1, y = -2 ----> -2 = m + b
when x = 4 y = 0 ----> 0 = 4m + b
subtract them
3m = 2
m = 2/3
m+b = -2
b = -2 - 2/3
b = -8/3

f(x) = (2/3)x - 8/3

Answer 2

You have a line through two points: (1,-2) and (4,0)
So, the slope is (0+2)/(4-1) = 2/3
Now use the point-slope form for the line, and you have
y-0 = 2/3 (x-4)