y = m x + b 2 = 6 m + b -4 = 8 m + b /*(-1 ) --------------------------- 2 = 6 m + b + 4 = - 8 m - b -------------------- 6 = - 2 m m = - 3 2 = 6 * ( - 3 ) + b 2 = - 18 + b b = 20 The equation is: y = - 3 x + 20 ( or in the other form: 3 x + y - 20 = 0 )