X - the cost of one night´s lodging y - the cost of a meal 3 x + 6 y = 132 3 x + 2 y = 109 / * (-1) ----------------------------- 3 x + 6 y = 132 -3 x - 2 y = - 109 ----------------------- 4 y = 23 y = 5.75 3 x + 34.50 = 132 3 x = 97.50 x = 97.50 : 3 x = $32.50 The cost of one night´s lodging is $32.50.