6x4+7x3-36x2-7x+6 4x4-4x3+13x2-6x+9

问题描述:

6x4+7x3-36x2-7x+6 4x4-4x3+13x2-6x+9

第一题:原式=6(x4+1)+7x(x2-1)-36x2
=6〔(x4-2x2+1)+2x2〕+7x(x2-1)-36x2
=6[(x2-1)2+2x2]+7x(x2-1)-36x2
=6(x2-1)2+7x(x2-1)-24x2
=[2(x2-1)-3x〕〔3(x2-1)+8x]
=(2x2-3x-2)(3x2+8x-3)
=(2x+1)(x-2)(3x-1)(x+3).