多项式乘以多项式的计算:(1)(2a+b)(a-2b)(2)(a+b)^2(3)(x^2+xy+y^2)(x^2-xy+y^2)(4)(2x^4-3x^3+5x^2+x)(-x+1)(5)(x+1)(x+2)(x+3)

问题描述:

多项式乘以多项式的计算:
(1)(2a+b)(a-2b)
(2)(a+b)^2
(3)(x^2+xy+y^2)(x^2-xy+y^2)
(4)(2x^4-3x^3+5x^2+x)(-x+1)
(5)(x+1)(x+2)(x+3)

(2a+b)(a-2b)=2a^2+ab-4ab-2b^2=2a^2-3ab-2b^2(a+b)^2=a^2+2ab+b^2(x^2+xy+y^2)(x^2-xy+y^2)=(x^2+y^2)^2-x^2y^2=x^4+2x^2y^2+y^4-x^2y^2=x^4+y^4+x^2y^2(2x^4-3x^3+5x^2+x)(-x+1)=2x^4-3x^3+5x^2+x-2...