Find the legs of a right-angled triangle if it is known that one of them is 7 cm larger than the other

Find the legs of a right-angled triangle if it is known that one of them is 7 cm larger than the other, and the hypotenuse of this triangle is 13 cm …

Let’s denote the smaller leg by x. Then the larger leg is x + 7.
The square of the hypotenuse with is equal to the sum of the squares of the legs.
c ^ 2 = 13 ^ 2 = x ^ 2 + (x + 7) ^ 2;
2 x ^ 2 + 14 x – 120 = 0;
x = (- 7 ± √ (49 + 240)) / 2 = (- 7 ± 17) / 2;
x1 = 5 cm;
x2 = -12 cm. The decision is not valid.