Hello!
Answer:

Explanation:
We want to find the value of x.
We know that the two figures have the same perimeter.
Let's calculate the perimeter of each figure:
Rectangle:

Square:

So, now, we have this equation:

Let's solve this equation to find the value of x:
▪ First, subtract 2x from both sides:

Simplify:

▪ Next, subtract 12 from both sides:

Simplify:

▪ Finally, divide both sides by 2:

Simplify:

Check:
Let's calculate the perimeters of each figure with x = 7:
Rectangle:

Square:

✔ So the check is good.
Conclusion:
The value of x is 7 cm.