1:(3x+3y)(x-y)
因式分解 (1)6(x-y)^3-3y(y-x)^2 (2)x(x-y)(a-b)-y(y-x)(
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
{3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1
计算:(x-y)(1/9x-y)-(1/3x-y)(1/3x+y)
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2
(x+2)(x+3) (x-4)(x+1) (y+4)(y-2) (y-5)(y-3)
设变量x,y满足约束条件x-y>-1,x+y>1,3x-y
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
y'=(x-y+1)/(x+y-3)通解
1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y)
2(x+y) 3x+3y=24 x+y/2x x y/2y= 1