先用(m除以(m+3))再加上(6除以(9-m的平方))然后再加上(2除以(m+3))

问题描述:

先用(m除以(m+3))再加上(6除以(9-m的平方))然后再加上(2除以(m+3))

M/(M+3)+6/(9-M^2)+2/(M+3)
=M/(M+3)+6/(3-M)(3+M)+2/(M+3)
=M(3-M)/(3-M)(3+M)+6/(3-M)(3+M)+2(3-M)/(3-M)(3+M)
=-(M+3)(M-4)/(M+3)(3-M)
=(4-M)/(3-M)