(2a-7)(a-1)+(2a-3)(2a+3)和3(a+1)二次方-5(a+1)(a-1)+2a(a-1)

问题描述:

(2a-7)(a-1)+(2a-3)(2a+3)和3(a+1)二次方-5(a+1)(a-1)+2a(a-1)

(2a-7)(a-1)+(2a-3)(2a+3)=2a^2-7a-2a+7+4a^2-9=6a^2-9a-2
3(a+1)^2-5(a+1)(a-1)+2a(a-1)=3(a^2+2a+1)-5a^2+5+2a^2-2a=4a+8