计算 m的平方-9分之12+3-m分之2

2个回答

=12/(m+3)(m-3)-2/(m-3)
=12/(m+3)(m-3)-2(m+3)/(m+3)(m-3)
=(12-2m-6)/(m+3)(m-3)
=-2(m-3)/(m+3)(m-3)
=-2/(m+3)