Question

已知|m+3|+(m+n+4)2=0,求:3mn-[2mn2-(2mn-m2n)-4m2]-mn的值。

Answer 1

解：∵|m+3|+(m+n+4)2=0
∴m+3=0，m+n+4=0
∴M=-3，N=-1
∴3mn-[2mn2-(2mn-m2n)-4m2]-mn
=3mn-2mn²+2mn-m²n+4m²-mn
=4mn-2mn²-m²n+4m²
把M=-3，N=-1代入4mn-2mn²-m²n+4m²
=4×﹙﹣3﹚×﹙﹣1﹚-2×﹙﹣3﹚×﹙﹣1﹚²-（-3）²×﹙﹣1﹚+4×﹙﹣3﹚²
=12+6+9+36
=63

Answer 2

|m+3|+(m+n+4)2=0

m+3=0,
m+n+4=0

m=-3,n=-1
3mn-[2mn2-(2mn-m2n)-4m2]-mn

=3mn-2mn2+(2mn-m2n)+4m2-mn
=3mn-2mn2+2mn-m2n+4m2-mn
=4mn-2mn2-m2n+4m2
=12+6+9+36
=63

Answer 3

已知|m+3|+(m+n+4)2=0,
m+3=0 m=-3
m+n+4=0 n+1=0 n=-1
3mn-[2mn2-(2mn-m2n)-4m2]-mn
=3mn-[2mn2-2mn+m2n-4m2]-mn
=3mn-2mn2+2mn-m2n+4m2-mn
=4mn-2mn2-m2n+4m2
=12+6+9+36
=63

Answer 4

由|m+3|+(m+n+4)2=0,知：m=-3,n=-1
带入式子，得值为，麻烦，自己算吧