4x+2y=55 怎么算 当4x+2y=55时 3x+2y=90 求x

4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? y=2x-4 当x 4x+2y=55 怎么算 当4x+2y=55时 3x+2y=90 求x 二元一次方程(x+y)/2+(x-y)/3=6,4(x+y)-5(x-y)=2怎么算 x(x+y)-(x-y)(x+y)-y^2,当x=4^-2007,y=-4^2008.我只想校对一下.急!我化出来原式=xy.然后结果怎么算! 当y=0求x怎么求?Y=4x^4-45x^2-49当y=0求x怎么求?Y=4x^4-45x^2-49 当x=2000,y=-10时计算x^2-2xy+y^2分之x^4-Y^4乘x^2+y^2分之y-x当x=2000,y=-10时计算x^2-2xy+y^2分之x^4-Y^4乘x^2+y^2分之y-x= [(2X+Y)*(2X+Y)-Y(Y+4X)]/2X 怎么算? 当x=-2,y=2/3求3y^4-4x^2y-4y^4+2x^2y-x^2y的值 当x=-2,y=2/3求3y^4-4x^2y-4y^4+2x^2y-x^2y的值 (x-y)^4·(x-y)-2(y-x)³·（y-x)²怎么算, x²-4y²+(x-2y) =(x+2y)(x-2y)+(x+2y) 接下来还怎么算? x^2-4xy+3y^2=（x-3y)(x-y)x^2-4xy+3y^2 怎么分解成（x-3y)(x-y) 当x=-1,y=2时怎么算 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 当x+y=2时7(x+y)一(x+y)+(x+y)=? (x-4y)(2x+y)= 已知2x+3y=4,当x=y时,x的值为