Question

求解几道方程组.加减法解下列1.2x+5y=83x+2y=52.2x+3y=63x-2y=-23.1/2X - 3/2Y

Answer 1

2x+5y=8

3x+2y=5

1*3-2*2

11Y=14,Y=14/11

2*5-1*2

11X=9,X=9/11

2.

2x+3y=6

3x-2y=-2

1*2+2*3

13X=6,X=6/11

1*3-2*2

14Y=22,Y=11/7

3.

1/2X - 3/2Y =-1

2x+y=3

1*4-2

2X-6Y=-4

-7Y=-7,Y=1 代人2

2x=2 x=1