ответ:
2sin(3x- pi/4) = - /sqrt{2}
sin(3x- pi/4) = - /frac{ /sqrt{2} }{2}
(3x- pi/4) = (-1)^{n+1} arcsin /frac{ /sqrt{2} }{2} + pin, n∈z
(3x- pi/4) = (-1)^{n+1} pi/4 + pin, n∈z
3x = (-1)^{n+1} pi/4 + pi/4 + pin, n∈z
x = (-1)^{n+1} pi/12 + pi/12 + (pin)/3, n∈z
