6*sin^2x+sinx*cosx-cos^2x=0
6sin^2x+sinxcosx-cos^2x-2sin^2x-2cos^2x=0
4sin^2x+sinxcosx-3cos^2x=0 :cos^2x
4tg^2x+tgx-3=0
tgx=-1
tgx=3/4
x=arctg3/4+Пk
x=-П/4+Пk