Given 2x2+x-a=5
⇒ 2(0)2+0-a=5 [putting x=0]
⇒ 0+0-a=5
⇒ a=-5
Hence, the value of a is -5.
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 \( \frac{k}{\alpha^2 \beta^2} = ? \)