\(20p=\textcircled{2} \times \textcircled{2} \times 5 \times \textcircled{p} \\
36p=\textcircled{2} \times \textcircled{2} \times 3 \times 3 \times \textcircled{p} \\
GCF(20p,36p)=\textcircled{2} \times \textcircled{2} \times \textcircled{p}=4p \\ \\
20p+36p=4p(5+9)\)
