use this equation : 3b=12 add the same the number to each side of the equation?

Dear Anonymous,

What you would typically want to do in this type of problem is to solve for the unknown quantity, which in your equation is b.

And whatever you do to one side of the equation, you must also do to the other side. So, if you want to isolate b in the equation 3b = 12, then you would divide both sides by 3. So,

3b/3 = 12/3, which as you see then works out to

b = 4.

* * *

However, if you really do need to add the same number to each side of the equation, then if you chose the number 4 for example, it might look like this:

3b + 4 = 12 + 4

3b + 4 = 16

Here, no number is being subtracted so we can't add any number, but here 3 is being multiplied so we can divide both sides by 3

3b/3 = 12/3

b = 4

This is the right answer if you want to solve it.

The question as you stated it does not ask for a solution.

It is a basic truth that when you manipulate two sides of the statement of an equality by addition, subtraction, multiplication, or division, the resulting statement is the equivalent of the first. (Division by zero is of course not allowed.)

Perhaps this problem is just for you to show that you know this basic truth.