When the side length of a square increases by 6 cm, its area increases by 96 square cm. What is its original area

When the side length of a square increases by 6 cm, its area increases by 96 square cm. What is its original area

Let X be the original length of the side
(X+6)²-X²=96
The solution is x = 5
So the original area is 5 × 5 = 25