Question

Упростите выражение
(a+9)² - 2(a+9)(a-5)+(a-5)²

Answer 1

$(a + 9) {}^{2} - 2(a + 9)(a - 5) + (a - 5) = a {}^{2} + 18a + 81 + ( - 2a - 18) \times (a - 5) + a - 5 = a {}^{2} + 18a + 81 - 2a {}^{2} + 10a - 18a + 90 + a - 5 = a {}^{2} + 81 - 2a {}^{2} + 10a + 90 + a - 5 = - a {}^{2} + 166 + 11a$