1.(m+1)(m^4-m³+m²-m+1)
=m^5-m^4+m³-m²+m+m^4-m³+m²-m+1
=m^5+1
2.(a+b)(a-2b)-(a+2b)(a-b)
=a²-2ab+ab-2b²-(a²-ab+2ab-2b²)
=a²-ab-2b²-a²-ab+2b²
=-2ab