ОДЗ
x ≠ - 3; x ≠ 0; x ≠ 3
27(x - 3) - 2(x - 3)(x + 3) - 3(x + 3) = 0
27x - 81 - 2(x^2 - 9) - 3x - 9 = 0
27x - 81 - 2x^2 + 18 - 3x - 9 = 0
- 2x^2 + 24x - 72 = 0 /:(-2)
x^2 - 12x + 36 = 0
(x - 6)^2 = 0
x = 6
К знаменателю 12, а к числителю 2
1)2-2сos²x-5cosx+1=0
2cos²x+5cosx-3=0
cosx=a
2a²+5a-3=0
D=25+24=49
a1=(-5-7)/4=-3⇒cosx=-3<-1 нет решения
a2=(-5+7)/4=1/2⇒cosx=1/2⇒x=+-π/6+2πn,n∈Z
2)sin2x+cos2x=0/cos2x≠0
tg2x+1=0⇒tg2x=-1⇒2x=-π/4+πn.n∈Z⇒x=-π/8+πn/2,n∈Z