因式分解:mn(x²+y²)+xy(m²+n²)

问题描述:

因式分解:mn(x²+y²)+xy(m²+n²)

mn(x²+y²)+xy(m²+n²)
=mnx²+mny²+xym²+xyn²
=mnx²+xym²+mny²+xyn²
=xm(n+ym)+ny(my+n)
=(xm+ny)(n+ym)