а) sinx + 2sinx(2x + π/6)=√3sin2x + 2
б) корни на отрезке [-7π/2; -2π]

sinx+2sin(2х+π/6)=√3sin2x+2sinx+2(sin2x•cosπ/6+cos2x•sinπ/6)=√3sin2x+2sinx+√3sin2x+cos2x=√3sin2x+2sinx+cos2x-2=0sinx+cos²x-sin²x-2=0sinx+1-2sin²x-2=02sin²x-sinx-1=0sinx=t2t²-t+1=0D=1+8=9t=(1±3)/4t1=1;t2=-1/2sinx=1;x=π/2+2πksinx=-1/2;x=(-1)ⁿ(-5π/6)+πk;k€Z