Persamaangaris yang melaluititik (3, 1) dan (4, 4)adalah

pers.grs.melalui ttk.(3,1)&(4,4) :
y-y1 / y2-y1 = x-x1 / x2-x1
y-1 / 4-1 = x-3 / 4-3
y-1 / 3 = x-3 / 1
3(x-3) = 1(y-1)
3x-9 = y-1
3x-y-9+1 = 0
3x-y-8 = 0
atau
3x-y = 8