<span>Воспользуемся формулой суммы тангенсов:</span>
<span>tg(x/3 + pi/4)+tg(x/3 - pi/4)=sin(2x/3)/(cos(x/3+pi/4)*cos(x/3-pi/4)=</span>
<span>sin(2x/3)/(0.5(cos(pi/2)+cos(2x/3))=2tg(2x/3)</span>
-4.1=1.5x+3.4
-4.1-3.4=1.5x
-7.5=1.5x
x=-1.5
!!!!!!!!!!!!!!!!!!!!!!!!!!!