How can you use expanded form to multiply a multi-digit number by a 1-digit number?

Plz hurry evaluate the expression a+b where a=8 and b=19

Alina fully simplifies this polynomial and then writes it in standard form. xy2 – 2x2y + 3y3 – 6x2y + 4xy2 if alina wrote the last term as 3y3, which must be the first term of her polynomial in standard form? xy2 5xy2 –8x2y –2x2y

Petes dog weighed 30 pounds it then lost 16% of it's weight how much did pete lose