(NEEDED ASAP) I already solved it and found that 240 is not a solution and I want to know whether or not I’m right.

Question

which is not a solution for 4sin² x - 1 = 0

1. 240
2. 330
3. 30
4. 150

Answer 1

4sin²x - 1 = 0

sin²x = 1/4

sinx = 1/2 or -1/2

sinx = 1/2 when x = 30° or 150°

sinx = -1/2 when x = 210° or 330°