<span>3x-8=-x
с x вправо, без x-влево (меняем знаки при переносе
3x+x=8
4x=8
x=8/4
x=2
Удачи)</span>
log3 x- log9 x+log81 x=3/4
ОДЗ x>0
log3 x - log3^2 x + log 3^4 x =3/4
log3 x -1/2 log3 x + 1/4 log x=3/4
log3 x (1-1/2+1/4)=3/4
3/4 log3 x=3/4
log3 x=1
<span>x=3
</span>
1)8х<=-16
х=-2
2) х=1
3) х=3
4) х= 4
sinx-cosx=0 или 1+2cosx=0
sinx=cosx |:cosx≠0 2cosx=-1
tgx=1 cosx=-1/2
x=π/4+πn; n∈z x=+-2π/3+2πn; n∈z
Ответ: <span>
π/4+πn; n∈z +-2π/3+2πn; n∈z</span>
log16 (1+cosπ/8)(1-cosπ/8)+2log16 cosπ/8= log16 (1-cos²π/8)+lod16 cos²π/8=
log16 (sin²π/8)+log16 cos²π/8= log(4²) (sin²π/8*cos²π/8=1/2log4 sin²π/8cos²π/8=
=log4 (sin²π/8cos²π/8)^1/2= log4(sinπ/8cosπ/8)=log4 (2sinπ/8cosπ/8)/2)=
=log4 (1/2sin π/4)=log4 1/2= 1/2*-1log2 2=-1/2
