Question

帮我解几道数学题

ab（c²-d²）+cd（a²—b²）
x²-4mx+8mn-4n²
8x⒋+64
x⒊-11x²+31x-21
我也在思考当中啊

Answer 1

1.原式=cda^2+(c^2-d^2)b*a-cdb^2--【主元】
=(ad+bc)(ac-bd)
2.原式=x^2-4mx+2n(4m-2n)
=(x+2n)(x+4m-2n)
3.原式=x^4+16x^2+64-16x^2
=(x^2+8)^2-16x^2
=(x^2-4x+8)(x^2+4x+8)
4.原式=x^3-x^2-10x^2+10x+21x-21
=x^2(x-1)-10x(x-1)+21(x-1)
=(x^2-10x+21)(x-1)
=(x-3)(x-7)(x-1)
楼主还有疑问可以再问我