2s-t=5
1 formula -2 formula ×2, get
3t+2t=5- 10
t=- 1
1 formula +2 formula ×3, get
4s+6s=5+ 15
s=2
(2)5X-6y=9
7x-4y=-5
1 formula ×2-2 formula ×3, get
10x-2 1x = 18+ 15
x=-3
1 formula ×7-2 formula ×5, get
-42y+20y=63+25
y=-4
(3)4x-3y= 14
5x+3y=3 1
1 type +2 type, obtained
4x+5x= 14+3 1
x=5
1 formula× 5-2 formula× 4, get
- 15y- 12y = 70- 124
y=2
(4) 3(x- 1)=y+5
5(y- 1)=3(x+5)
The transformation of formula 1 is 3x-3 = y+5 = ×-y = 8.
The variation of Formula 2 is: 5y-5 = 3x+15 = "3x-5y =-20.
Type 3+type 4, get
-y-5y=8-20
y=2
3 ×5-4, get
15x-3x=40+20
x=5