2 x - 5 y = 18 / * 4 3 x + 4 y = 4 / * 5 ( we will use the addition method ) -------------------------- 8 x - 20 y = 72 + 15 x + 20 y = 20 ----------------------- 23 x = 92 x = 92 : 23 x = 4 8 - 5 y = 18 - 5 y = 18 - 8 - 5 y = 10 y = 10 : ( - 5 ) y = - 2 Answer: ( x, y ) = ( 4, - 2 )
