first step: simplify each term
first step pt A- apply distribute property: -2a^2b+a^2 -5ab+ 3ab^2 -b^2 +2(a^2b) +2 (2ab)
first step part B -multiply 2 by 2: -2a^2b +a^2 -5ab +3ab^2 -b^2 +2a^2b + 4ab
second step: simplify by adding terms( in the picture)
