Question

помогите 4-ое задание

Answer 1

(а-3)(а+3)-(8+а)
$(a - 3)(a + 3) - (8 + a) { = }^{2} : a {}^{2} - 9 - (8 + a) {}^{2} = - 9 \ \a {}^{2} (64 + 16 + a {}^{2} ) = 0 \ \ - 64 - 16a = 0 \ - 16 = 64 \ a = - 4$