<u>Answer:</u> The equivalent expression of the given terms is 13 p
<u>Step-by-step explanation:</u>
Like terms are defined as the terms which have same variable. Mathematical operation are applied on these terms.
Unlike terms are defined as the terms which do not have same variable. Mathematical operation are not applied on these terms.
<u>For Example:</u> 
In the above expression,
are the like terms because they have same variable which is '
'
In the given expression: 12 p + p
Both the terms are like terms, and thus the operation can be applied.
Hence, the equivalent expression of the given terms is 13 p