3 ms·
More generally, (n x 10 + 5)^2 = 100n^2 + 2 x 5 x 10n + 25 = 100n^2 + 100n + 25 = n(n + 1) x 100 + 25
by lovelearning 11y ago
More generally,
(n x 10 + 5)^2 = 100n^2 + 2 x 5 x 10n + 25 = 100n^2 + 100n + 25 = n(n + 1) x 100 + 25
loading thread…