Log₅ (2x² - 3x - 1) > 0
5 > 0
2x² - 3x - 1 > 5⁰
2x² - 3x - 1 - 1 > 0
2x² - 3x - 2 > 0
D = 9 + 4*2*2 = 25
x₁ = (3 - 5)/4
x₁ = - 1/2
x₂ = (3 + 5)/4
x₂ = 2
+ - +
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- 1/2 2 x
x∈(- ≈; - 1/2) (2;+ ≈)
Решение
√(8/3) - √(50/3) ] : √(2/75) =
= [2√(2/3) - 5√(2/3)] : √(2/75) = [- 3*√(2/3)] : √(2/75) = - 3 * √25 = - 3*5 = - 15