1.
cos(-pi/3)=cos(pi/3)=1/2
2.
(2/3)^x=8/27
(2/3)^x=(2/3)³
x=3
3.
(a^(1/5))^20=a^(20/5)=a⁴
4.
㏒₆9+㏒₆4=㏒₆(9*4)=㏒₆36=2
5.
f(x)=(4-2x)^(1/6)
4-2x≥0
x≤2
x∈(-беск;2]
6.
f(x)=tg3x
f'(x)=3/(соs²3х)
7.
∫³₁(4x³-4x+1)dx=(x⁴-2x²+x)|³₁=(3⁴-2*3²+3)-(1⁴-2*1²+1)=66
8.
4/(∛x+2)+(∛x+3)/5=2
(26+5∛x+x^(2/3))/(5(2+∛x))=2
26+5∛x+x^(2/3)=10(2+∛x)
6-5∛x+x^(2/3)=0
y=∛x
y²-5y+6=0
(y-3)(y-2)=0
y-3=0 или y-2=0
y=3 или y=2
∛x=3 или ∛x=2
x=27 или x=8
дальше не понимаю, увы.