We are given a mathematical expression as follows:
We are asked to simply the above expression.
Whenever we resolve mathematical operators in an expression/equation we use the guidelines of PEMDAS.
The rule PEMDAS gives us the order in which the mathematical operations are carried out. The acronyms full form is:
Mathematical operators are applied in the order of decreasing importance in an expression as expressed above.
Now, we will go ahead an apply the rule of PEMDAS to simplify our expression. We see that we have to deal with a P: Parenthesis first!
Next we will use the Multiplication operator ( M ) and multiply out the respective terms inside the parenthesis as follows:
Since the above terms ( 21r ) and ( 3 ) are of different domains i.e one is a multiple of a vraible ( r ) and the other one is an integer we can not further simplify the result. Hence, the simplified expression would be: