6(x^4)(y^3)+3Xy(^a)+2x(^2)y(^7)-3y(^8)是按y的升幂排列的,那么（a-2)(a-4)可能的值是多少?

（X-3xy+4xy-y）-[-2x-2（xy-3/2xy）-y]+6xy的过程 xy-2{xy-[3x^2y-(4xy^2+0.5xy)]+4x^2y}+6xy^2 已知A=X-2y+2xy,B=3x-6y+4xy 求3A-B 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 5x^3y*(-3y)^2+(-6xy)^2*(-xy)+xy^3*(-4x^2) xy>0,x不等于y,比较loga(3x^2+4xy+y^2)与loga(2x^2+6xy)大小.(a不等于1,a>0) 已知A = x³ - 2y³ + 3x²y + xy² - 3xy + 4 ,B = y³ - x³ - 4x²y - 3xy - 3xy² + 3 ,C = y³ + x²y + 2xy² + 6xy - 6 试说明无论x,y,z取何值,A+B+C恒为常数. 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) 已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y答案是1/x-1/y=2(y-x)/xy=2 得：x-y=-2xy(3x+7xy-3y)/(2x-3xy-2y)=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy)=xy/(-7xy)=-1/7 谁能帮我解释一下=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy) 是怎 x^+2xy+y^+4=16 x^-2xy+y^=16 求(3xy+6y^)+|x^-(2xy+2y^-3x^)|的值 已知A=x^3-2y^3+3x^2y+xy^2-3xy+4,B=y^3-x^3-4x^2y-3xy-3xy^2+3,C=y^3+x^2y+2xy^2+6xy-6试说明对于xyz的任何值A+B+C都是常数 ... 已知A=x³-2y³+3x²y+xy²-3xy+4,B=y³-x³-4x²y-3xy-3xy²+3.C=y³+x²y+2xy²+6xy-6,试说明对于xyz的任何值A+B+C是常数. 1.b^2+4a(b+a)2.9x^2y+y^3-6xy^2 因式分解30题(要过程)am+an+bm+bn x^2+5y-xy-5x x2+xy+2xz+x (a+b)x-(b+a)y -12x(x-y)-(y-x)x^2 2x^2+4x+2 x(x+z)-y(y+z) 2(x^2-3ab)+x(4a-3b) 4x^2+12xy+9y^2-25 x^4-16 16x^4-1 x^2+9x+8 x^2-10xy+24y^2 2x^2+15xy-8y^2 3x^2-6xy+3y^2 24x^2+22x-21 -x^2+4xy- 2a^2(3a^2-2a+1)+4a^3 (-2x^2y+6x^3y^4-8xy)÷(-2xy) (2x+y)^2-(2x+3y)(3x-3y) 4xy-[(x²+5xy-y²)-(3xy-1/2y)]x=3,y=-6 【x(xy-xy)-y(x-xy)】÷3xy 已知A=8x^2y-6xy^2-3xy,B=7xy^2-2xy+5x^2y求A-B