计算题,有过程最好,有答案也行.x(x+1)+(2-x)(2+x) ,(a+1/2b)(a-1/2b)-(3a-2b)(3a+2b)
问题描述:
计算题,有过程最好,有答案也行.x(x+1)+(2-x)(2+x) ,(a+1/2b)(a-1/2b)-(3a-2b)(3a+2b)
答
x(x+1)+(2-x)(2+x)
=x²+x+2-x²
=x+2
(a+1/2b)(a-1/2b)-(3a-2b)(3a+2b)
=a²-1/4b²-9a²+4b²
=-8a²+15/4b²
=(15b²-32a²)/4