Answer:
D
Explanation:
perimeter of square = 4 length of its sides
x represents the side lengths
y represents the perimeter of the a square
y = ax + b
a = slope = y2-y1 / x2 -x1
= 8-4 / 2-1 = 4
y = 4x + b
from any point (1,4 )
4 = 4 .(1) + b
b= 0
y = 4x