因式分解2x(l-2m)-y(l+3n)+2(3nx+my)(x平方-5x+5)(x平方-5x-7)+113x平方-11
1个回答
拆开原式=2x-4mx-3ny-y+6nx+2my
合并同类项,有原式=2x(1-2m+3n)-y(1-2m+3n)
=(2x-y)(1-2m-3n)
2.分析5+-7=-2,-2/2=-1,所以原式=(x^2-5x-6)(x^2-5x+4)
=(x+1)(x-6)(x-4)(x-1)
3.合并同类项得3x^2-(11y+z)x+2(y-z)(3y+z)
十字相乘得（3x-2y+2z)(x-3y-z)
4.如果不懂因式定理的话,全拆开.
原式=a^2 *(b-c)+b^2 *(c-a)+ c^2* (a-b)=a^2*b-a^c+b^2*c-b^2*a +c^2* (a-b)=
=ab(a-b)-(a^2-b^2)c+c^2* (a-b)=(a-b)(ab-ac-bc+c^2)
=(a-b)(a-c)(b-c)
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