tentukan persamaan garis lurus yang melalui a.(2,3) b.(4,7)

(x1,y1) = (2,3)
(x2,y2) = (4,7)

Pers. garisnya :
y-y1 / y2-y1 = x-x1 / x2-x1
y-3 / 7-3 = x-2 / 4-2
2(y-3) = 4(x-2)
y-3 = 2x-4
2x-y = 1