<span>10х-20+8х+16=х</span>² ==> 18x -4 = х² ==> х² - 18x + 4 = 0
1) 27у^3 / 8х^5
2) -4х^10 у^2 / с^4
3) -(2х-7) / 22а^2b^3 × 11a^5b^6 / (2x-7)(2x+7) = -a^3b^3 / 2(2x+7)
4) 5(a-b)(a+b) / 5(a-2b) × a(a-2b) / (a-b)^2 = a(a+b) / (a-b)
5) (x-2y)^4 / x^2(x+2)^2 × (x+3y)^3 / x^3(x-2y)^3 = x^2-xy-2y^2 / x^5
Cos(3x-π/2)=sin3x
sin3x=1/2
3x=π/6+2πk⇒x=π/18+2πk/3,k∈z
3x=5π/6+2πk⇒x=5/18+2πk/3,k∈z
1)π<π/18+2πk/3≤3π/2
18<1+12k≤27
17<12k≤26
17/12<k≤26/12
k=1 x=π/18+2π/3=25π/18
2)π<5π/18+2πk/3≤3π/2
18<5+12k≤27
13<12k≤22
13/12<k≤22/12
нет решения
Ответ x=π/18+2πk/3,k∈z;x=5/18+2πk/3,k∈z;x=25π/18