(m-5n)(m-n)-6(m+2n)(m-3n)
问题描述:
(m-5n)(m-n)-6(m+2n)(m-3n)
答
(m-5n)(m-n)-6(m+2n)(m-3n)
=m²-6mn+5n²-6(m²-3mn+2mn-6n²)
=m²-6mn+5n²-6m²+6mn+36n²
=-5m²+41n²