(1).将Y=1,带入5X+2Y=16,即5X+2=16,5X=14,X=14/5 (2).将Y=3/4X代入X-8Y=-15,即X-3/4X=-15,1/4X=-15,X=-60 (3).2X/3+5Y=2 ①,X/6-2Y=2 ②, ①×2+②×5得,X=84/13,-6/13 (4).2X+3y-z=11 ①,2x+y-5z=8 ②,-2x+7y+z=19 ③, ①+③得,10y=30,即y=3, ①-②得,4z=-3, 即z=-3/4,x=5/8,应该是对的
求采纳.啊
(1).将Y=1,带入5X+2Y=16,即5X+2=16,5X=14,X=14/5 (2).将Y=3/4X代入X-8Y=-15,即X-3/4X=-15,1/4X=-15,X=-60 (3).2X/3+5Y=2 ①,X/6-2Y=2 ②, ①×2+②×5得,X=84/13,-6/13 (4).2X+3y-z=11 ①,2x+y-5z=8 ②,-2x+7y+z=19 ③, ①+③得,10y=30,即y=3, ①-②得,4z=-3, 即z=-3/4,x=5/8,应该是对的
求采纳.啊