Réponse :
Explications étape par étape
Kevin notes that:
5² - 4² = 9 and 5 +4 = 9
10² -9² = 19 and 10 + 9 = 19
250² - 249² = 499 and 250 + 249 = 499
and therefore, he asserts that the difference between the squares of two consecutive numbers is equal to the sum of these two numbers.
Let's prove he's right?
Let x and x-1 be the two consecutive numbers
Difference of squares: x² - (x-1) ² = x² - (x² -2x + 1) = x² -x² + 2x -1
= 2x -1
= x + x -1
sum of these two numbers: x + (x-1)
and so Kevin is right:
The difference between the squares of two consecutive numbers is equal to the sum of these two numbers.