(2a+b-c+5)(2a-b+c+5)如何计算?
问题描述:
(2a+b-c+5)(2a-b+c+5)如何计算?
答
{(2a+5)+(b-c)}{(2a+5)-(b-c)}=(2a+5)^2-(b-c)^2=4a^2+20a+25-b^2+2bc-c^2
(2a+b-c+5)(2a-b+c+5)如何计算?
{(2a+5)+(b-c)}{(2a+5)-(b-c)}=(2a+5)^2-(b-c)^2=4a^2+20a+25-b^2+2bc-c^2