m²+7mn-18n²-5m+43n-24=m²-2mn+9mn-18n²+3m-8m+27n+16n-24 =(m²-2mn+3m)+(9mn-18n²+27n)-(8m-16n+24)=m(m-2n+3)+9n(m-2n+3)-8(m-2n+3)=(m+9n-8)(m-2n+3)a^3b-ab^3+a²+b²+1=...