x+y=70 2x-4y=80怎么解,
X+Y=5.7 1/4X+2/5Y=4/5X 怎么解
5x+4y=22 4x+y=3y+x 怎么解
这题怎么解?X-Y=4,2X+Y=20,X=?Y=?3X+2Y=14,2X-3Y=5,X=?Y=?
怎么解二元一次方程组2(x-y)/3-x+y/4=-1和6(x+y)-4(2x-y)=16
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20
{(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6
已知4x=9y求(1)x+y/y (2)y-x/2x
(x+y)(x+2y)(x+3y)(x+4y)=-40