Question

The ordered pairs listed below are points on a line.

(1, 5), (3, 11), (5, 17)
Which of the following equations best describes the line containing all three points?

Answer 1

y = 3x + 2

Explanation:

change in y ÷ change in x = gradient

6 ÷ 2 = 3

3 = gradient

equation of a straight line

y = mx + c

5 = 3(1) + c

5 = 3 + c

c = 2

confirmation

11 = 3(3) + c

11 = 9 + c

c = 2 (same = right)

substitute back in y = mx + c

y = 3x + 2