Prove that \((6p) × (3r) × (p + 2)\) \(=\) 18\(p^{2}  r\) \(+\) 36\(pr\).
 
Proof:
 
\((6p) × (3r)\) \(=\)
 
\(\times\) \((p + 2)\)
 
The above product is expanded using .
 
The first term is expanded as follows:
 
18\(pr\)\(\times\) \(p\) \(=\) 18\(p^{1+1}  r\)   [By ]
 
\(=\) 18\(p^{2}  r\)
 
The second term is expanded as follows:
 
18\(pr\)\(\times\) \(2\) \(=\) 18 \(\times 2\) \(p \times r\)
 
\(=\) \(pr\)
 
Combine the terms.
 
\((6p) × (3r) × (p + 2)\) \(=\) 18\(p^{2}  r\) \(+\) \(pr\).
 
Hence, proved.