Simplify $2a - 5\left( {a + 1} \right)?$

Hint: According to the question we have to determine the multiplication of the terms of the expression which is as given in the question $2a - 5\left( {a + 1} \right)$. So, first of all we have to open all the brackets and for the expression $2a - 5\left( {a + 1} \right)$ there is only one smaller bracket.
Now, we have to multiply all the variables with the other variables or with the same variable and we have to do the same for all the constant terms which are mentioned in the question.
Now, we have to add the terms of the expression which can be any variable or any constant term and same as we have to subtract the terms of the expression which can be any variable or any constant term.

Complete step by step answer:
Step 1:
First of all we have to open all the brackets and for the expression $2a - 5\left( {a + 1} \right)$ there is only one smaller bracket which is as mentioned in the solution hint. Hence,
$ \Rightarrow 2a - 5 \times a - 5$

Step 2:
Now, we have to multiply all the variables with the other variables or with the same variable and we have to do the same for all the constant terms which are mentioned in the question.
$ \Rightarrow - 3a - 5$

Step 3:
Now, we have to add the terms of the expression which can be any variable or any constant term and same as we have to subtract the terms of the expression which can be any variable or any constant term but there is no such term which can be added or subtracted.
$ \Rightarrow - 3a - 5$

Hence, we have obtained the solution or we can say that the multiplication of the expression $2a - 5\left( {a + 1} \right)$ which is $ \Rightarrow - 3a - 5$.

Note: To obtain the multiplication it is necessary that we have to open all the brackets and then we have to multiply the variable with any other variable.
If a variable is multiplied with any other variable such as when a is multiplied with the same variable then it will become as a square, as ${a^2}$.