Question

if f(x) is a linear function that passes through the points (4,3) and (-4,-9), what is the y-intercept of f(x) ?

Answer 1

The gradient of the line is calculated as (3 - (-9))/(4 - (-4)) = 1.5

Writing it in point-slope form, you get y-3 = 1.5(x-4)

This gives y = 1.5x - 3 giving a y-intercept of -3.