Respuesta :

sin(3pi-x)=sinx
divide by sin
3pi-x=x
2x=3pi
x = 3/2 pi

Sub x into equation:
sin(3pi-(3/2)pi)=sin(3/2pi)
3pi-(3/2)pi=3/2pi
3pi=(3/2)pi+(3/2)pi
3pi=3pi