18sin2(x)-35sin(x)+12=0=(2sin(x)-3)(9sin(x)-4).
Since sin(x) cannot exceed 1, sin(x)=4/9, x=sin-1(4/9)=26.3878° approx.
x can also be 180-26.3878=153.6122°. Other solutions are found by adding 360° to these values, or by subtracting 360°. No interval has been specified.