Решение:x - 2 =
20 - x² = x² + 4x + 4
16 - 2x² + 4x = 0
x² - 2x - 8 = 0
D₁ = k² - ac = 1 + 8 = 9;
= 3
x₁ = 1 + 3 = 4
y₁ = x - 2 = 2
x₂ = -2
y₂ = -4
Ответ: (4; 2), (-2; -4)
1) 0.9 это 25\% от 3.6
2) 999 это 33.1/3 от 3000
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Tg2x = -3/√3
tg2x = - √3
2x = -arctg √3 + πn
2x = - π/3 + πn
x = - π/6 + πn/2
π/3 ≤ - π/6 + πn/2 ≤ 3π/2
2π ≤ - π + 3πn ≤ 9π
3π≤ <span>3πn ≤ 10π
1 </span>≤ n ≤ 10/3
n = 1 n = 2 n = 3
x = π/3 x = 5π/6 x = 4π/3
Количество корней: 3