Question

m^2(2次方）－n^2+3m-3n＝0,求（m^3n-2m^2n^2=mn^3)/(2mn)+2mn的值

Answer 1

m^2-n^2+3m-3n＝0

(m+n)(m-n)-3(m-n)=0

(m-n)(m+n-3)=0

m-n=0或m+n-3=0

（m^3n-2m^2n^2+mn^3)/(2mn)+2mn

=（m^3n-2m^2n^2+mn^3+4m^2n^2)/(2mn)

=（m^3n+2m^2n^2+mn^3)/(2mn)

=mn(m+n)^2/2mn

=(m+n)^2/2

若m-n=0,则m=n

原式=2m^2或2n^2

若m+n-3=0,则m+n=3

原式=9/2