初一数学题（因式分解） 初二数学题因式分解
\u521d\u4e00\u6570\u5b66\u9898\uff08\u56e0\u5f0f\u5206\u89e3\uff09\u2235x²y+xy²=880;xy+x+y=71
xy(x+y)=880
\u2234\u53ef\u4ee5\u628axy,x+y\u770b\u505a\u65b9\u7a0ba²-71a+880=0\u4e24\u6839
\u89e3\u5f97a1=55,a2=16
\u2235x,y\u4e3a\u6b63\u6574\u6570\uff0c55\u4e0e16\u4e0d\u76f8\u90bb\uff0c\u5373x\u548cy\u22601
\u2234xy\uff1ex+y
\u2234x+y=16,xy=55
\u89e3\u5f97x=11,y=5,\u6216x=5,y=11
\u22343x²+8xy+3y²
=3\u00d7121+3\u00d725+8\u00d711\u00d75
=878
55555555555555555555551. \u539f\u5f0f=-a(a^4-1)
=-a\uff08a^+1\uff09(a^-1)
=-a(a^+1)(a+1)(a-1)
2.\u539f\u5f0f=3((m+n)^-9n^)
=3(m+n+3n)(m+n-3n)
=3(m+4n)(m-2n)
\uff08a^2+1)(a+1)(1-a)a(\u63d0\u53d6-a\u7136\u540e\u5c31\u5f88\u81ea\u7136 \u4f60\u4e5f\u53ef\u4ee5\u628a\u8fd9\u4e2a\u5f0f\u5b50\u91cd\u65b0\u5408\u4ee5\u4e0b\u518d\u53cd\u8fc7\u6765\u5c31\u4f1a\u4e86\uff09
2 =3\uff08\uff08m+n)^2-9n^2)
=3(m^2+2mn-8n^2)
=3(m+4n)(m-2n)
=(x^2+x-3)*(x^2-x-3)
2）x^4-14*x^2+1
=(x^2-4*x+1)*(x^2+4*x+1)
3）x^4-47*x^2+1
=(x^2-7*x+1)*(x^2+7*x+1)
4）x^2-y^2+2*x+6*y-8
(x-2+y)*(x+4-y)
5）m^4+4n^4
=(m^2-2*m*n+2*n^2)*(m^2+2*m*n+2*n^2)
6）x^2*y^2-x^2*z^2-y^2*z^2+z^4
=(y-z)*(y+z)*(-z+x)*(x+z)
7）x^5+x^4+x^3+x^2+x+1
=(x+1)*(x^2+x+1)*(x^2-x+1)
1）x的4次方-7x的2次方+9
=(x^4-6x^2+9)-x^2
=(x^2-3)^2-x^2
=(x^2-3+x)(x^2-3-x)
2）x的4次方-14x的2次方+1
=(x^4-2x^2+1)-12x^2
=(x^2-1)^2-12x^2
=(x^2-1+2根号3*x)(x^2-1-2根号3*x)
3）x的4次方-47x的2次方+1
=(x^4-2x^2+1)-45x^2
=(x^2-1)^2-45x^2
=(x^2-1+3根号5*x)(x^2-1-3根号5*x)
4）x的2次方-y的2次方+2x+6y-8
=(x^2+2x+1)-(y^2-6y+9)
=(x+1)^2-(y-3)^2
=(x+1+y-3)(x+1-y+3)
=(x+y-2)(x-y+4)
5）在m、n都是大于1的整数时，m的4次方+4n的4次方是合数
m^4+4n^4
=(m^4+4m^2n^2+4n^4)-4m^2n^2
=(m^2+2n^2)^2-4m^2n^2
=(m^2+2n^2+2mn)(m^2+2n^2-2mn)
因为m,n都是整数，所以原式是二个整数的积，即是一个合数。
6）x的2次方乘y的2次方-x的2次方乘z的2次方-y的2次方乘z的2次方+z的4 次方
=x^2(y^2-z^2)-z^2(y^2-z^2)
=(y^2-z^2)(x^2-z^2)
=(y+z)(y-z)(x+z)(x-z)
7）x的5次方+x的4次方+x的3次方+x的2次方+x+1
=(x-1)(x^5+x^4+...+x+1)/(x-1)
=(x^6-1)/(x-1)
=(x^3+1)(x^3-1)/(x-1)
=(x+1)(x^2-x+1)(x-1)(x^2+x+1)/(x-1)
=(x+1)(x^2-x+1)(x^2+x+1)
1 (x^2-x-3)(x^2+x-3)
2 (x^2-4x+1)(x^2+4x+1)
3 (x^2-7x+1)(x^2+7x+1)
4 (x+y-2)(x-y+4)
5 m^4+4n^4=(m^2-2mn+2n^2)(m^2+2mn+2n^2)
6 (x-z)(x+z)(y-z)(y+z)
7 (x+1)(x^2-x+1)(x^2+x+1)
1)(x2+x-3)(x2-x-3)
2）（x2+4x+1）（x2-4x+1）
3)太无聊了，不做了
在这里我实在不好回答你,留个e-mail吧
再次对百度上这种问题的泛滥感到担忧
1)x的4次方-6x的平方+9-x的平方=(x的平方-3x)的平方-x的平方=
(X的平方-2X)*(X的平方-4X)=X的平方*(X-2)*(X-4)
4)(X+1)的平方-(Y-3)的平方=(X+Y-2)*(X-Y+4)
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