(4a-b)^2-[8b(1-a)-(3a-b)(3a+b)],其中a=-1/5,b=1/2
问题描述:
(4a-b)^2-[8b(1-a)-(3a-b)(3a+b)],其中a=-1/5,b=1/2
求值
答
(4a-b)^2-[8b(1-a)-(3a-b)(3a+b)]
=(4a-b)^2-[8b-8ab-9a^2+b^2]
=25a^2-8b
=25*(-1/5)^2-8*(1/2)
=1-4
=-3