Question

已知,m平方=n+2,n平方=m+2(m不等于n),求：m立方-2mn+n立方的值（注意：最后求的是m立方-2mn+n立

Answer 1

m^2=n+2,n^2=m+2.

m^3-2mn+n^3

=m^3-mn+n^3-mn

=m(m^2-n)+n(n^2-m)

=m(n+2-n)+n(m+2-m)

=2m+2n

=2(m+n)