若a-b=2,a-c=1,求(a-2b+ c)2的值

问题描述:

若a-b=2,a-c=1,求(a-2b+ c)2的值

∵a-b=2,a-c=1
∴c-b=(a-b)-(a-c)
=2-1
=1
(a-2b+ c)²
=(a-b+c-b)²
=(2+1)²
=9