9. If the length of a rectangle is reduced by 3 cm and the width is increased by 2 cm, a square with the same area as the original rectangle is obtained, then the perimeter of the rectangle is $\qquad$ cm.
【Analysis】According to the problem, we can assume the side length of the square is $a$, then the original rectangle's length is $a+3$, and the width is $a-2$. By the equality of areas, we can derive a relationship to find the value of $a$, which will allow us to determine the perimeter of the rectangle.

【Solution】Solution: According to the analysis, assume the side length of the square is $a$, then the original rectangle's length is $a+3$, and the width is $a-2$, so:
$a \times a=(a+3) \times(a-2)$, solving this gives: $a=6$, hence the length of the rectangle is: 9, and the width is 4, the perimeter of the rectangle $=2 \times(4+9)=26$ (cm).

Therefore, the answer is: 26.