Решение
1) log₅log₅ (5)¹/²⁵ = log₅ (1/25)log₅ 5 = log₅ 5⁻² = - 2
2) lg²x⁵ / [lgx³lgx¹/² = [ lgx⁵ * lgx⁵] / [2*lgx * (1/2)*lgx] =
= [5*lgx * 5 * lgx] / [lgx*lgx] = 25
3) log₂ (3x² - 10x) = 3
ОДЗ: 3x² - 10x > 0
x(3x - 10) = 0
x₁ = 0
x₂ = 10/3
x₂ = 3(1/3)
x∈ (- ∞ ; 0) (3(1/3) ; + ∞)
3x² - 10x = 2³
3x² - 10x - 8 = 0
D = 100 + 4*3*8 = 196
x = (10 - 14)/6
x = - 4/6
x₁ = - 2/3
x = (10 + 14)/6
x₂ = 4
Ответ: x₁ = - 2/3 ; x₂ = 4
4) log₃ (- x + 9) < 3
ОДЗ: - x + 9 > 0
-x > - 9
x < 9
x ∈ (- ∞ ; 9)
Так как 3 > 1, то
- x + 9 < 3³
- x < 27 - 9
- x < 18
x > - 18
С учётом ОДЗ x ∈ (- 18 ; 9)
Ответ: x ∈ (- 18 ; 9)
(c-d)(c+d)=c^2-d^2
(b-a)^2=b^2-2ab+a^2
(x+y)(x-y)=x^2-y^2
(a+b)^2=a^2+2ab+b^2
(x-y)^2=x^2-2xy+y^2
(a+b)^2=a^2+2ab+b^2
√3sin²x-0,5sin2x=0
√3sin²x-sinxcosx=0
sinx(√3sinx-cosx)=0
sinx=0⇒x=πn,n∈z
√3sinx-cosx=0
2(√3/2sinx-1/2cosx)=0
2sin(x-π/6)=0
x-π/6=πk
x=π/6+πk,k∈z