Question

Спростіть вираз
(k-5)(k+5)-k(k-4)​

Answer 1

Ответ:

$1)(k - 5)(k + 5) - k(k - 4) = \\ {k}^{2} + 5k - 5k - 25 - {k}^{2} + 4k = \\ - 25 + 4k \\ 2)(a + 4 {)}^{2} + (a - 9)(a + 25) = \\ {a}^{2} - 8a + 16 + {a}^{2} + 25a - 9a - 225 = \\ 2 {a}^{2} + 8a - 209 \\ 2)(a + 4 {)}^{2} + (a - 9)(a + 25) = \\ {a}^{2} + 8a + 16 + ( {a}^{2} + 25a - 9a - 225) = \\ {a}^{2} + 8a + 16 + {a}^{2} + 25a - 9a - 225 = \\ 2 {a}^{2} + 24a - 209$