Question

Write the equation of the line that passes through the points (1, 7) and (5, 15) using function notation.

a) y = 2x + 5
b) y = 4x + 8
c) f(x) = 2x + 5
d) f(x) = 4x + 8

Answer 1

c) f(x) = 2x + 5

Explanation:

slope = (y2-y1)/ (x2-x1)

m = (15-7)/(5-1)

m = 8/4

m=2

point slope form for an equation is

y-y1 = m(x-x1)

y-7 = 2 (x-1)

distribute

y-7 = 2x-2

add 7 to each side

y-7+7 = 2x-2+7

y = 2x +5

it asks for the equation in function notation

f(x) = 2x+5