(1-m/m+3)÷(m^2-9)/(m^2+6m+9)怎么化简？ 2m-6+ 2m+2 m-3

(1-m/m+3)÷(m^2-9)/(m^2+6m+9)怎么化简？2m-6+ 2m+2 m-3

先化简再求值：mm+3-6m2+6m+9÷2m+3，其中m=-2

原式=

m+3 -

(m+3)2 ×

m+3

m+3 -

m+3

m-3

m+3 ，

当m=-2时，原式=

-2-3

-2+3 =-5．

(m-3除以3m的2次方-6m)除以(m+2-m-2分之5)

=(m-3)/(3m^2-6m)÷[m+2-5/(m-2)]

=(m-3)/3m(m-2)÷[(m+2)(m-2)-5]/(m-2)

=(m-3)/3m(m-2)÷[(m^2-4-5]/(m-2)

m-1+2m-6/m^2-9除以2m+2/m+3

=m-1+2m-6/m^2-9乘以m+3/2m+2

=m-1+2(m-3)/m-3乘以1/2(m-1)

=m-1+2乘以1/2(m-1)

=m-1+1/m-1

=m-1/m-1+1/m-1

=m/m-1

m(3m-1)-(m+3)(m-3)-2(m-1)^2

=3m^2-m-(m^2-9)-2(m^2-2m+1)

=3m^2-m-m^2+9-2m^2+4m-2

=3m^2-m^2-2m^2-m+4m-2+9

=3m+7

=3*(-1/2)+7

=-3/2+7

=11/2