Chapter 5 - Section 5.4 - Multiplying Polynomials - Exercise Set - Page 289: 42

$4y^2+20y-11$

Using special products techniques, the given expression is equivalent to \begin{align*} & [(2y+5)+6][(2y+5)-6] \\\\&= (2y+5)^2-6^2 \\\\&= (2y)^2+2(2y)(5)+(5)^2-36 \\\\&= 4y^2+20y+25-36 \\\\&= 4y^2+20y-11 .\end{align*}