Prove that \((6a) × (2c) × (a + 3)\) \(=\) 12\(a^{2}  c\) \(+\) 36\(ac\).
 
Proof:
 
\((6a) × (2c)\) \(=\)
 
\(\times\) \((a + 3)\)
 
The above product is expanded using .
 
The first term is expanded as follows:
 
12\(ac\)\(\times\) \(a\) \(=\) 12\(a^{1+1}  c\)   [By ]
 
\(=\) 12\(a^{2}  c\)
 
The second term is expanded as follows:
 
12\(ac\)\(\times\) \(3\) \(=\) 12 \(\times 3\) \(a \times c\)
 
\(=\) \(ac\)
 
Combine the terms.
 
\((6a) × (2c) × (a + 3)\) \(=\) 12\(a^{2}  c\) \(+\) \(ac\).
 
Hence, proved.