解二元一次方程组 (1) x+1=5(y+2) 3(2x-5)-4(3y+4)=5 (2)y⼀3-x+1⼀6=3 2(x-y⼀2)=3(x+y⼀18)

(1)题目可以化为x+1=5y+10，6x-15-12y-16=5，也就是x-5y=9…… ①，x-2y=6……②，②-①
得3y=-3，于是就有y=-1；将y=-1代入①式得x=4，即x=4；y=-1
（2）同理，y=17/9 ;x=-119/54

（1）6x-15-12y-16=5
6x-12y-36=0
约分
x-2y-6=0
x=6+2y带入 x+1=5(y+2)
6+2y+1=5y+10
2y-5y=10-1-6
-3y=3
y=-1带入 x-2y-6=0
x-2x(-1)-6=0
x+2-6=0
x=4

(2)2x-y=3x+1/6y
2x-3x=1/6y+y
-x=7/6y
x=-7/6y 带入y/3-x+1/6=3

1/3y-(-7/6y)+1/6=3
1/3y+7/6y+1/6-3=0
2/6y+7/6y+1/6-18/6=0
9/6y-17/6=0
乘以6
9y-17=0
9y=17
y=17/9 带入x=-7/6y
x=-7/6乘以17/9=-119/54

(1) x+1=5(y+2)
x+1=5y+10
x=5y+9
3(2x-5)-4(3y+4)=5
6x-15-12y-16=5
6(5y+9)-15-12y-16=5
30y-12y=-18
18y=18
y=1
x=14

(1) y=-1,x=4
(2)y=17/9 ;x=-119/54