The product of two numbers is 168 and the sum of their square is 289. The sum of the numbers is:

Question: The product of two numbers is 168 and the sum of their square is 289. The sum of the numbers is:

Solution:
Let
the numbers be x and y

Then,
xy = 168
and x² + y² = 289

∴ (x + y)² = x² + y² + 2xy
= 289 + (2 × 168)
= 289 + 336
= 625

∴ x + y = √625 = 25