分解因式:(1)-2x5n-1yn+4x3n-1yn+2-2xn-1yn+4;(2)x3-8y3-z3-6xyz;(3)
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/15 14:31:01
分解因式:
(1)-2x5n-1yn+4x3n-1yn+2-2xn-1yn+4;
(2)x3-8y3-z3-6xyz;
(3)a2+b2+c2-2bc+2ca-2ab;
(4)a7-a5b2+a2b5-b7.
(1)-2x5n-1yn+4x3n-1yn+2-2xn-1yn+4;
(2)x3-8y3-z3-6xyz;
(3)a2+b2+c2-2bc+2ca-2ab;
(4)a7-a5b2+a2b5-b7.
(1)原式=-2xn-1yn(x4n-2x2ny2+y4)
=-2xn-1yn[(x2n)2-2x2ny2+(y2)2]
=-2xn-1yn(x2n-y2)2
=-2xn-1yn(xn-y)2(xn+y)2.
(2)原式=x3+(-2y)3+(-z)3-3x(-2y)(-z)
=(x-2y-z)(x2+4y2+z2+2xy+xz-2yz).
(3)原式=(a2-2ab+b2)+(-2bc+2ca)+c2
=(a-b)2+2c(a-b)+c2
=(a-b+c)2.
本小题可以稍加变形,直接使用公式,解法如下:
原式=a2+(-b)2+c2+2(-b)c+2ca+2a(-b)
=(a-b+c)2.
(4)原式=(a7-a5b2)+(a2b5-b7)
=a5(a2-b2)+b5(a2-b2)
=(a2-b2)(a5+b5)
=(a+b)(a-b)(a+b)(a4-a3b+a2b2-ab3+b4)
=(a+b)2(a-b)(a4-a3b+a2b2-ab3+b4).
=-2xn-1yn[(x2n)2-2x2ny2+(y2)2]
=-2xn-1yn(x2n-y2)2
=-2xn-1yn(xn-y)2(xn+y)2.
(2)原式=x3+(-2y)3+(-z)3-3x(-2y)(-z)
=(x-2y-z)(x2+4y2+z2+2xy+xz-2yz).
(3)原式=(a2-2ab+b2)+(-2bc+2ca)+c2
=(a-b)2+2c(a-b)+c2
=(a-b+c)2.
本小题可以稍加变形,直接使用公式,解法如下:
原式=a2+(-b)2+c2+2(-b)c+2ca+2a(-b)
=(a-b+c)2.
(4)原式=(a7-a5b2)+(a2b5-b7)
=a5(a2-b2)+b5(a2-b2)
=(a2-b2)(a5+b5)
=(a+b)(a-b)(a+b)(a4-a3b+a2b2-ab3+b4)
=(a+b)2(a-b)(a4-a3b+a2b2-ab3+b4).
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