已知a+b=4,b-c=5,则代数式a2+2b2+c2+2ab-2bc=_.
问题描述:
已知a+b=4,b-c=5,则代数式a2+2b2+c2+2ab-2bc=______.
答
a2+2b2+c2+2ab-2bc,
=a2+2ab+b2+b2-2bc+c2,
=(a+b)2+(b-c)2,
=42+52,
=41.
故答案为:41.