5a平方-[a的平方+(-x+y)]
问题描述:
5a平方-[a的平方+(-x+y)]
答
=5a²-a²-(-x+y)
=4a²+x-y
5a平方-[a的平方+(-x+y)]
=5a²-a²-(-x+y)
=4a²+x-y