x+y=20 ,(2x)/(3y)=1:2怎么解..
x-y=2y 0.2x+3y=1 这个二元一次方程怎么解?
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
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2
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
4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
这题怎么解?X-Y=4,2X+Y=20,X=?Y=?3X+2Y=14,2X-3Y=5,X=?Y=?
解方程组:1、6(x-y)-2(x-y)=14 2、3(x-y)+(x+y)+5 怎么解
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
2(x+y) 3x+3y=24 x+y/2x x y/2y= 1
微分方程 (x^2)*y"-x*y'+y=1怎么解呢?