3x-5=4y ②
(1) times 2, and you get
10x+4y=34③
③+②, get
13x=39
x=3
Substitute x=3 into ① to get 15+2y= 17.
y= 1
2.3x-2y=-7①
2x+5y=8②
①x2,get 6x-4y=- 14③。
②x3, you get 6x+ 15y=24④.
④-③. Obtain
19y=38
y=2
Substituting y=2 into ② gives 2x+ 10=8.
2x=-2
x=- 1
3.2y+8=x①
4x+2y= 1 1②
②-①. Obtain
4x-8= 1 1-x
5x= 19
x= 19/5
Substitute x= 19/5 into ① to get
2y+8= 19/5
2y= 19/5-8
2y=-2 1/5
y=-2 1/ 10
4.7x- 13y=25①
9x- 15= 17y②
① Multiply 9 to get 63x- 1 17y=225③.
② Multiply 7 to get 63x-105 =119y④.
④-③. Obtain
- 105+ 1 17y = 1 19y-225
-2y=- 120
y=60
Substitute y=60 into ① to get.
7x-780=25
7x=805
x= 1 15