Question

100-(a+5)²=?
(2a+3b)²-(3a-b)=?
(12-a)(12+a)=?
Пожалуйста решите

Answer 1

$100 - {(a + 5})^{2} = \\ = 100 - {a}^{2} - 10a - 25 = \\ = - {a}^{2} - 10a + 75$

${(2a + 3b)}^{2} - (3a - b) = \\ = 4 {a}^{2} + 12ab + 9 {b}^{2} - 3a + b$

$(12 - a)(12 + a) = \\ = 144 - {a}^{2}$