8х^2-3x^2+4x-5x+38-86=0
5x^2-x-48=0
D=1-4*5*(-48)=1+960=961
x1=(1+корень из961)/2*5=(1+31)/10=32/10=3,2
х2=(1-31)/10=-3
Первое задание..............
Tg 6x = -√3
6x = arctg(-√3) + πk , k ∈Z
6x = -π/3 + πk , k ∈Z
x = -π/18 + πk/6 , k ∈Z
3. (x² - 2x)² - 7 (x² - 2x) - 8 = 0
t² - 7t - 8 = 0
t = 8
t = -1
x² - 2x = 8
x² - 2x = -1
x = 4
x = -2
x = 1
x₁ = -2, x₂ = 1, x₃ = 4
4. (x⁴ - 3x + 1) * (x² - 3x + 3) = 3
x⁴ = 3x³ + 3x² - 3x³ + 9x² - 9x + x² -3x + 3 = 3
x⁴ = 3x³ + 3x² - 3x³ + 9x² - 9x + x² -3x = 0
x⁴ - 6x³ + 13x² - 12x = 0
x * (x³ - 6x² + 13x - 12) = 0
x * (x³ - 3x² - 3x² + 9x + 4x - 12) = 0
x * (x² * (x-3) - 3x * (x-3) + 4 (x-3)) = 0
x * (x-3) * (x² - 3x + 4) = 0
x = 0
x - 3 = 0
x² - 3x + 4 = 0
x = 0
x = 3
x ⊄ R
x = 0
x = 3
x₁ = 0, x₂ = 3
5. (7x-2)² - 12 * I7x - 2I - 28 = 0
t² - 12 * ItI - 28 = 0
t = 14
t = -14
7x - 2 = 14
7x - 2 = -14
x =
x =
x₁ = , x₂ =