\(^o^)/~①x+y=38 3*x/2=1/2(10+y/3)②x+y=15 17000x+18000y=26500

来源：学生作业帮编辑：神马作文网作业帮分类：数学作业时间：2024/10/05 16:32:28

\(^o^)/~
①x+y=38 3*x/2=1/2(10+y/3)
②x+y=15 17000x+18000y=265000
③y-0.75x=25 0.9x-y=20
④x+y=240 6x=10y
⑤x+y=50000 0.05x+0.075y=3000
⑥4(y-x)=100 0.8(x+y)=100
⑦15y=x+5 17(y-1)=x+4

$\(^o^)/~①x+y=38 3*x/2=1/2(10+y/3)②x+y=15 17000x+18000y=26500$

1.
x+y=38 ①
9x-y=30 ② ①+②得
x=6.8 y=31.2
2.
x+y=15 ①
17x+18y=265 ② ①*18-②得
x=5 y=10
3.
4y-3x=100 ①
9x-10y=200 ② ①*3+②得
x=300 y=250
4.
x+y=240 ①
6x-10y=0 ② ①*10+②得
x=150 y=90
5.
x+y=50000 ①
2x+3y=120000 ② ②-①*2得
x=30000 y=20000
6.
y-x=25 ①
x+y=125 ② ①+②得
x=50 y=75
7.
15y-5=x ①
17y-21=x ② ②-①得
x=115 y=8

先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y 已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 10/x+y+3/x-y=-5 15/x+y-2/x-y=-1（用换元法解此方程组） 2(x+y) 3x+3y=24 x+y/2x x y/2y= 1 2x²-3xy=y²=0（x,y不得o）求x/y+y/x 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20