Question

若(m^2-n)^2+M=(m^2+n)^2,则M的值是

Answer 1

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

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

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

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

=2m^2×2n

=4m^2·n

故选A