2元一次方程组!急6x=5y1.｛300+4x+100=4y4(x+y)=802.｛5(x-y)=80 x+y=153.

2元一次方程组!急
6x=5y
1.｛
300+4x+100=4y
4(x+y)=80
2.｛
5(x-y)=80
x+y=15
3.｛
(1+15%)x+(1+10%)y=17
2x+y+6=22
4.｛
x+y+2=14
y-x=45
5.｛
(85%y-x)×8=(y-35-x)×12
0.7×(1+40%)x+0.9×(1+40%)y=399
6.｛
(1+4%)x+(1+40%)y=490
y
x + — =50
7.｛ 2
2
— x+y =50
3
x+y=102
8.｛
12x+10y=1118
6x=5y
1.｛
300+4x+100=4y