用简便方法解方程组3(x+y)+2(x-y)=36,2(x+y)-3(x-y)=24

2024-12-20 10:22:16
推荐回答(4个)
回答1:

3(x+y)+2(x-y)=36 (1)
2(x+y)-3(x-y)=24 (2)
(1)式乘以2,(2)式乘以3
得出6(x+y)+4(x-y)=72 (3)
6(x+y)-9(x-y)=72 (4)
(3)-(4)得出
13(x-y)=0
x-y=0 (5)
(1)式乘以3,(2)式乘以2
得出9(x+y)+6(x-y)=108 (6)
4(x+y)-6(x-y)=48 (7)
(6)+(7)
13(x+y)=156
x+y=12 (8)
(5)+(8)
x=6
y=6

回答2:

3(x+y)+2(x-y)=36,2(x+y)-3(x-y)=24
化简得 5x+y =36 ,-x +5y =24

5x+y =36 得y=36-5x ,代入-x +5y =24

解得,x=6
所以y =36-5x =6

回答3:

3(x+y)+2(x-y)=36

5x+y=36 1
2(x+y)-3(x-y)=24

-x+5y=24 2
2*5+1 y+25y=156
y=6
将y=6代入1 5x+6=36
x=6

回答4:

3(x+y)+2(x-y)=36
2(x+y)-3(x-y)=24

3x+3y+2x-2y=36
2x+2y-3x+3y=24

5x+y=36
-x+5y=24

5x+y=36
-5x+25y=120

5x+y-5x+25y=36
26y=156
解得y=6
x=6