How do you solve for \[2w\] in \[P = 21 + 2w\] ?

Hint: In this question, they have given a simple equation \[P = 21 + 2w\] and asked us to solve for \[2w\]in it. Since the equation in itself is not clear and contains two unknown values, we can only represent the value like that. Here we simply need to transfer the numbers or variables which are not the required one to the other side and derive the solution.

Complete step-by-step solution:
Here, we are given a simple equation and asked to solve for \[2w\] in it.
The given equation is \[P = 21 + 2w\], we need to find the value of \[2w\] in this.
Since the equation is very simple and contains more than one unknown value, the solution will also be like that.
So here \[P = 21 + 2w\],
We need to separate the variable \[2w\] from the other numbers and variables.
Transferring the number $21$ to the other side we get,
\[ \Rightarrow 21 + 2w = P\]
On rewriting we get,
\[ \Rightarrow 2w = P - 21\]

Therefore the value of \[2w\] is $P - 21$.

Note: Students may go wrong or get confused when rearranging the equation or separating the variables and the numbers. We have to transfer the numbers or the coefficients’ to one side. When transferring any variable or numbers to the other side, the signs of the same will be changed to its opposite sign.
For example, addition will become subtraction, subtraction will become addition, multiplication will become division and then division will become multiplication. This is the basic rule. This is done because addition and subtraction have an inverse relationship. As well, multiplication and division also have inverse relationships. That’s why when transferred to the other side its nature changes.