Problem # $9$ Add the following polynomials $($bytes$)$ in the quotient ring

$Z_2$ :

a$){?}^6{57}^{\text{'}}+{?}^{\text{'}}{02}^{\text{'}}$

b$)\text{'}{03}^{\text{'}}+{?}^{\text{'}}03\text{'}$

c$)\text{'}FF\text{'}+\text{'}0F\text{'}$

Hint: see AES

Problem # $10$ Multiply the following polynomials $($bytes$)$ in the quotient ring:

$Z_2$

a$)\text{'}{57}^{\text{'}}**\text{'}02\text{'}$

b$)\text{'}57**\text{'}{04}^{\text{'}}$

c$){657}^{\text{'}}**\text{'}\text{'}\text{'}$

Hint: see AES