1/12x+1/12X(1-40%)Y=1 1/15x+1/15X(1+20%)Y=1 解的X=3 ,
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
y=(x^2+x)/(x+1)
函数,y=3x/(x^2+x+1) ,x
函数y=3x/(x^2+x+1) (x
已知x:y=3:1,且x+y=12,求x-y的值.
解方程组:(x+3)(y-2)=(x-3)(y+10),(x+1)(y+3)=(x-2)(y+12)
1、x(x-y)(x+y)-x(x+y)^2
x^3+x-30(分解因式);x^12-y^12;x^15+x^14+x^13.x^2+x+1
若x-y=1,求代数式x(x-y)+y(y-x)+2013的值
{3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2