怎么解下列方程组?(1).X=Y+1 Y+X=5 (2)2X-3Y=4 1/2Y-X=1 (3)X+2=3Y 2X=3Y (4)3X+7=7 5X-2Y=8

问题描述:

怎么解下列方程组?(1).X=Y+1 Y+X=5 (2)2X-3Y=4 1/2Y-X=1 (3)X+2=3Y 2X=3Y (4)3X+7=7 5X-2Y=8
(5)2X+3Y=5 4X-Y=3 (6)3X-2Y=4 5X+3Y-13=0 (7)X+5Y=12 2X-5Y=-6 (8)X-3Y=-3 3X+Y=11 (要写过程)

(1)x=y+1 ①y+x=5 ②将①代如②式解得2y=4,即y=2再将y带入①解得x=3(2)2X-3Y=4 ①1/2Y-X=1 ②①+②x2解得x= -5/2,y=-3(3)X+2=3Y ①2X=3Y ②②带入①解得x=2,y=4/3(4)3X+7=7 ①5X-2Y=8 ②解得 x=0,y=-4(5)2X+3Y=5...