(x-1)(x-3)(x+5)(x+7)=297
[(x-1)(x+5)] [(x-3)(x+7)] = 297
(x² + 5x - x - 5)(x²+7x-3x-21) = 297
(x² + 4x - 5)(x² + 4x - 21) = 297
x² + 4x= m
(m - 5)(m - 21) = 297
m² - 21m - 5m + 105 = 297
m² - 26m - 192 = 0
D/4 = 169 +192= 361
m ₁,₂ = 13 + - √361= 13 + - 19
m₁ = 32 m₂ = - 6
x² + 4x - 32= 0 x² + 4x + 6 = 0
x₁ = -8 x₂ = 4 D/4 = 4 - 6 < 0 решений нет
Теперь вроде порядок)