The area of a rectangle pool was 120 square meters. If the long side is 7 meters plus a number and the width is 6 meters. What is the value of the variable?

I couldn't make a equation for this; I tried and I got 7+x+6 = 120 and that doesn't seem right.

You are correct to feel ill at ease. You have confused area and perimeter. You want

(x+7)(6) = 120

To solve this problem, you need to set up the equation correctly. Let's break it down step by step:

1. Start by identifying the variables in the problem. You know that the long side of the rectangle equals 7 meters plus a number, so let's call that number "x". The width is given as 6 meters.

2. The formula for the area of a rectangle is length multiplied by width. In this case, the length is 7 + x. So, the equation for the area of the rectangle can be written as:
(7 + x) * 6 = 120

3. Now, you can solve the equation for the value of x. Multiply 6 by each term in the parentheses:
42 + 6x = 120

4. Next, isolate the variable term by subtracting 42 from both sides of the equation:
6x = 120 - 42
6x = 78

5. Finally, solve for the value of x by dividing both sides of the equation by 6:
x = 78 / 6
x = 13

Therefore, the value of the variable x is 13.