tentukan persamaan garis melalui (4,-2) dan (1,7)

y - y1 / y2 - y1 = x - x1 / x2 - x1
y -(-2) / 7 -(-2) = x - 4 / 1 - 4
y + 2 / 7 + 2 = x - 4 / - 3
y + 2 / 9 = x - 4 / - 3
-3(y + 2) = 9(x - 4)
-3y - 6 = 9x - 36
-3y = 9x - 36 + 6
-3y = 9x - 30
y = 9x/-3 - 30/ - 3
y = -3x + 10