1:4(x-100)+3y=5 2:6(x-y)-2(x+y )=14 x-100=-y 3(x-y)+(x+y)=5 先无视上面的1.4(x-100)+3y=5x-100=-y2.6(x-y)-2(x+y )=143(x-y)+(x+y)=5

1:4(x-100)+3y=5 2:6(x-y)-2(x+y )=14 x-100=-y 3(x-y)+(x+y)=5 先无视上面的1.4(x-100)+3y=5x-100=-y2.6(x-y)-2(x+y )=143(x-y)+(x+y)=5
1:4(x-100)+3y=5 2:6(x-y)-2(x+y )=14 x-100=-y 3(x-y)+(x+y)=5
先无视上面的
1.
4(x-100)+3y=5
x-100=-y
2.
6(x-y)-2(x+y )=14
3(x-y)+(x+y)=5

1:4(x-100)+3y=5 2:6(x-y)-2(x+y )=14 x-100=-y 3(x-y)+(x+y)=5 先无视上面的1.4(x-100)+3y=5x-100=-y2.6(x-y)-2(x+y )=143(x-y)+(x+y)=5
化简：4x-400+3y=5
x+y=100
即4x+3y=405 1
3x+3y=300 2
1-2得x=105
代入得y=-5