[tex]\begin{gathered} a)\text{ (x + 2)(x + 6)} \\ equivalent\text{ expression} \\ x^2\text{ + 6x + 2x + 12} \\ x^2\text{ + 8x + 12} \end{gathered}[/tex][tex]\begin{gathered} b)\text{ (x + 5)(2x + 10)} \\ 2x^2\text{ + 10x + 10x + 50} \\ 2x^2\text{ + 20x + 50 equivalent expression} \end{gathered}[/tex]