4(y+1)+4(1-x)-4(x+y) 化简
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
化简:[(2x-y)平方+(2x+y)(2x-y)-4x(x-y+1)]÷2x
1) (2x+5y)(2x-5y)(-4x^2-25y^2) 2) [(x+y)(x-y)-(x-y)^2+2y(x-y
(x+2)(x+3) (x-4)(x+1) (y+4)(y-2) (y-5)(y-3)
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
1 4(x-y+1)+y(y-2x)
{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
把4(x-y+1)+y(y-2x)因式分解
4(x-y+1)+y(y-2x)
已知4x=9y求(1)x+y/y (2)y-x/2x
化简,并求值2(x-2y)²-4(x+3y)(x-3y)-2(x-y).(y+x)-5(-x-1)²