1)4-2x=+-2π/3+2πn
-2x=+-2π/3-4+2πn
x=+-π/3-2+2πn
2)6+3x=+-3π/4+2πn
3x=+-3π/4-6+2πn
x=+-π/4-2+2πn/3
3)cos (2x + π/4) =-1/√2
2x+π/4=+- 3π/4+2πn
2x=+- 3π/4-π/4+2πn
2x=π/2+2πn U 2x=-π+2πn
x=π/4+πn U x=-π/2+πn
4)cos (π/3 - 3x) = √3 /2
π/3-3x=+-π/6+2πn
-3x=+-π/6-π/3+2πn
-3x=-π/6+2πn U -3x=-π/2+2πn
x=π/18+2πn/3 U x=π/6+2πn/3