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因式分解:因式分解:(y^2+3y)^2-(2y+6)^2a^4+a^2b^2-b^2c^2-c^2m^4-18m^2+17分组分解法:3m^2+2n-2mn-3ma^2-b^2+2bc-c^2

题目详情
因式分解:
因式分解:(y^2+3y)^2-(2y+6)^2
a^4+a^2b^2-b^2c^2-c^2
m^4-18m^2+17
分组分解法:3m^2+2n-2mn-3m
a^2-b^2+2bc-c^2
▼优质解答
答案和解析
1.(y^2+3y)^2-(2y+6)^2
=[(y^2+3y)+(2y+6)][(y^2+3y)-(2y+6)]
=(y^2+5y+6)(y^2+y-6)
=(y+2)(y+3)(y-3)(y+2)
=(y+2)^2(y+3)(y-3)
2.a^4+a^2b^2-b^2c^2-c^2
=(a^4-c^4)+(a^2b^2-b^2c^2)
=(a^2+c^2)(a^2-c^2)+b^2(a^2-c^2)
=(a^2-c^2)(a^2+c^2+b^2)
=(a+c)(a-c)(a^2+b^2+c^2)
3.m^4-18m^2+17
=(m^2-17)(m^2-1)
=(m+√17)(m-√17)(m+1)(m-1)
4.3m^2+2n-2mn-3m
=(3m^3-3m)+(2n-2mn)
=3m(m-1)-2n(m-1)
=(m-1)(3m-2n)
5.a^2-b^2+2bc-c^2
=a^2-(b^2-2bc+c^2)
=a^2-(b-c)^2
=(a+b-c)(a-b+c)