(4x+5xy)(2x-y) (1-x+y)(x+y) 把0.00003051精确到十万分位 把0.00003051精确到0.0000013a*a-5a(3b-a)+2a(-4a-5/2 b),其中a=1/5,b=-1/3x(x-y)-y(y-x)+(x-y)(x-y),其中x=-1,y=2若a的n+1次方乘以a的m+n次方=a的六次方,且m-2n=1,求m的6次

x²-y²+5x+3y+4（x+y-2xy)(x+y-z)+(xy-1）² 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) (-2xy+2x+5y)-(3xy+2y-2x)-(x+4y+xy)其中x-y=4xy=-1 若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] x-y/x^2+xy除以xy-x^2/x^2y^2-x^4*1/x-y 整式乘法..1.3xy（x²y-xy²+xy）-xy²（2x²-xy+2x）2.（x-1）（x²-4x+3）-x（x²-5x+2) 先化简,再求值：-4x+7x-5-3x-6x+2,其中x=-2分之1 4xy-3x-xy先化简,再求值：-4x+7x-5-3x-6x+2,其中x=-2分之14xy-3x-xy+y+x-3xy-2y+2x+x,其中x=-5,y=-1 5xy平方-2x平方y+[3xy平方-(4xy-2x平方y-2x平方y)],其中x=-2,y=-1求值 已知1/x+1/y=5,求x+y+3xy/2x-4xy+2y的值,已知1/x+1/y=5,x+y+3xy/2x-4xy+2y的值, x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² 计算x²-x/x²×x/1-x和x²-4y²/x²+2xy+y²÷x+2y/x²+xy 4xy-[(x²+5xy-y²)-(3xy-1/2y)]x=3,y=-6 若1/X-1/Y=3,求5X+2XY-5Y/X-4XY-Y 若1/x-1/y=3,求5x+2xy-5y/x-4xy-y的值 已知1/X-1/Y=5 ,则x-2xy-y/4x+3xy-4y 已知2/x-1/y=3,则(2y-x+4xy)/(3x-6y-5xy)=?