化简1.(3y-2y+z)(3y-2y-z)2.(2a+b-c+3d)(2a-b+c+3d)计算(1+1/2)[1+1/(2^2)][1+1/(2^4)][1+1/(2^8)]+1/(2^15)化简求值(x-y)^2*(x^2+xy+y^2)^2-(x^3+y^3)*(-x^3+y^3)其中x=1,y=-1不好意思，第一题确实打错了。是(3x-2y+z)(3x-2y-z)但不能用

3(y-2)^2-(2y+z)(-z+2y) 1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) 2(x+y)(x+y-z)+3(y-z)(x+y-z) 因式分解3(y-z)的平方-(2y+z)(2y-z)因式分解3(y-z)^2-(2y+z)(-z+2y) 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 3(y-z)²-(2y＋z)(-y＋2y) 化简(x+Y)^2(y+z-x)(z+x-y)+(x-y)^2(x+y+z)(x+y-z) 分式加减的几道题目求速度1 .(x+y)²/（x-z)(y-z) - (y+z)²/（x-z)(y-z) = 2.2x+3y/x-y+2y/y-x-3y/x-y= 急 x,y,z均为正整数,x>=y,y>=z,z>=8 x+3y-z=急x,y,z均为正整数,x>=y,y>=z,z>=8x+3y-z=132,请问1.x+y+z有最小值782.x+y+z有最大值1343.洽有一组解(x,y,z)使得x+y+z有最大值4.x+3y有最小值1405.x+2y有最大值130 (x-3y+2z)(x+3y-2z) （x-2y+3z)(x+2y-3z) (2y-x-3z)(-x-2y-3z) 化简(y-x)(z-x)/(x-2y+z)(x+y-2z)+（z-y)(x-y)/(x-2z+y)(y+z-2x)+(x-z)(y-z)/(y+z-2x)(x-2y+z) 2(x+y-z)-3(x-y+z)-5(x+y-z)+6(x-y+z) 计算 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 (x+3y-2z)(x-3y-2z)-(x+3y-2z)^2 化简 [x^3(y^2-z^2)+y^3(z^2-x^2)+z^3(x^2-y^2)]/[x^3(y-z)+y^2(z-x)+z^3(x-y)]=是y^3.正确的是化简 [x^3(y^2-z^2)+y^3(z^2-x^2)+z^3(x^2-y^2)]/[x^3(y-z)+y^3(z-x)+z^3(x-y)]=