x^4=-1

(X-1)(X-2)=X*X-3X+2X*X-3X+2=(X-1)(X-3)X*X+4X+4=X(X-4)+4X*X+Y*Y=(X+Y)(X-Y)哪一个因式分解是正确的第一个正确.其余正确形式是：X*X-4X+3=(X-1)(X-3)X*X

x^2+x^-2=x^4,化简(x+x^-1+x2)(x-x^-1+x²)（-x+x^-1+x²）(x+x^-1-x²)第18题,

(x-3/x-2)-(x-2/x-1)=(x-5/x4)-(x-4/x-3)

x(x+1)+(x+2)+(x+3)+(x+4)+(x+5)=27求xx²＋x＋x＋2＋x＋3＋x＋4＋x＋5=27x²＋5x＋14=27x²＋5x－13=0x=(－5±√77)/2无解X=2没有实数解吧！化简

提取公因式:已知x*x-5x+1=0求x*x*x-4x*x-4x-1即x²-5x=-1所以原式=x³-5x²+x²-5x+x-1=x(x²-5x)+(x²-5x)+x-1=-x-1

X+X+X+(X-1)+(X-2)+(X-3)+(X-4)=10(X-3)+(X-4)7x-10=11x-34-4x=-24x=6

x+2/x+1-x+4/x+3=x+6/x+5-x+8/x+7x=?x+2/x+1-x+4/x+3=x+6/x+5-x+8/x+71+1/(x+1)-1-1/(x+3)=1+1/x+5)-1-1/(x+7)1/(x+1)+1/(x+7)=1

解方程(x/x(x+2))+(x/(x+2)(x+4))+.+x/(x+8)(x+10)=1(x/x(x+2))+(x/(x+2)(x+4))+.+x/(x+8)(x+10)=(x/2)*(2/x(x+2))+(2/(x+2)(x+4))+

x^4+x^3+x^2+x+1=0,x^2006+x^2005+x^2004+x^2003+x^2002=x^2002(x^4+x^3+x^2+x+1)=0提取公因式就行了提取公因式原式=x^2002*(x^4+x^3+x^2+x+1)=0

x*x*(1/4)=20x两边乘4x²-80x=0x(x-80)=0x=0,x=80

1.用公式计算：COSX=1-X*X/2!X*X*X*X/4!-X*X*X*X*X*X/6!.直到最后一项的绝对这是cosx在x=0处泰勒展开式

4x^-4x+1=x^+6x+9化简得3x^2-10x-8=0a=3b=-10c=-8由公式法得x1=4x2=-2/34

4x-4x+1=x+6x+93x-10x-8=0(x-4)(3x+2)=0x=4或x=-2/3

（X+4)(x-2)(x-4),其中x=-1）原式=x3-2x2-16x+32,当x=-1时,原式=-1-2+16+32=45；(x+4)(x-2)(x-4)=(x-2)(x-16)x=-1代入-3×(1-16)=-3×(-15)=45

[3/x]-[4/x-1]=6/x-x²[3/x]-[4/x-1]=6/x-x²3（x-1)+4x=-63x-3+4x=-63x+4x=-6+37x=-3x=-3/7

[3/x]-[4/x-1]=6/x-x²x=3,通分即可1+x²=5/x

求x:|x|-|x-4|=0.5x-1x>4时x-x+4=0.5x-1x=100x+x-4=0.5x-1x=2x-x+x-4=0.5x-1x=-6当x＜0时，－x-4+x=0.5x-1；x=-6当0≤x≤4时，x-4+x=0.5x-1；x=

(x^2+x-1)(x^2+x+2)=4(x^2+x-1)(x^2+x+2)=4(x^2+x)^2+(x^2+x)-2-4=0(x^2+x)^2+(x^2+x)-6=0(x^2+x-2)(x^2+x+3)=0(x-1)(x+2)(x^2+x

(x-2)(x+1)(x+4)(x+7)=19注意:[(x-2)(x+7)]*[(x+1)(x+4)]=19(x平方+5x-14)*(x平方+5x+4)=19设x平方+5x=a,则(a-14)(a+4)=19a平方-10a-56=19a平方

(x+1)(x+2)(x+3)(x+4)=24x=0,解得x=0