(i)4y–7z : Type of polynomial - Binomial
(ii)y2: Type of polynomial - Monomial
(iii)x+y–xy: Type of polynomial - Trinomial
(iv)100: Type of polynomial - Monomial
(v)ab–a–b: Type of polynomial - Trinomial
(vi)5–3t: Type of polynomial - Binomial
(vii)4p2q–4pq2 : Type of polynomial - Binomial
(viii)7mn: Type of polynomial - Monomial
(ix)z2–3z+8 : Type of polynomial - Trinomial
(x)a2+b2: Type of polynomial - Binomial
(xi)z2+z: Type of polynomial - Binomial
(xii)1+x+x2: Type of polynomial - Trinomial
If \( x, y \) are two positive integers such that \( x + y = 20 \) and the maximum value of \( x^3 y \) is \( k \) at \( x = a, y = \beta \), then \( \frac{k}{\alpha^2 \beta^2} = ? \)