Did I do this right? Just want to make sure.

15 = r-1
+ 6 +6

r = 21

You need to get the unknown on one side of the equation and the known on the other side.

15 = r-1

Add 1 to both sides of the equation.

15 + 1 = r -1 + 1
16 = r

Here's how we can prove it.
Substitute 16 for r.

15 = 16 - 1

Yep. We have the right answer.

Thank you Ms. Sue for the explanation. I'm sorry, I accidentally wrote -1 instead of -6. It was supposed to be 15 = r-6.

Your original answer of 21 is correct. :-)

thank you, and sorry once again for my mistake.

You're very welcome.

We're all human and make typos and other mistakes. :-)

To confirm if you did it correctly, let's go through the steps to solve the equation.

1. Start with the original equation: 15 = r - 1.

2. The goal is to isolate the variable "r" on one side of the equation. In this case, we want to get rid of the "-1" term on the right side.

3. To eliminate the "-1" term, we can add 1 to both sides of the equation:
15 + 1 = r - 1 + 1

Simplifying this:
16 = r.

4. Now, we have "16 = r." However, in your answer, you wrote "r = 21." So, it seems like there might be an error.

Therefore, based on the steps, it appears that you made a mistake in your calculations. The correct answer is "r = 16," not "r = 21."