Tolong bantuannya kak soal matematika ! pake cara yah !

Bab Trigonometri
Matematika SMA Kelas X

28]
Tripel Pitagoras
6, 8, 10
x, y, r

◎◎◎kuadran I◎◎◎
sin 3x + sin x
= 2 sin ((3x + x)/2) cos ((3x - x)/2)
= 2 sin 2x cos x
= 2 . 2 . sin x . cos x . cos x
= 4 . 8/10 . 6/10 . 6/10
= 4 . 4/5 / 3/5 / 3/5
= 144/125

29]
sin (x - 210°) + sin (x + 210°)
= 2 sin ((x - 210° + x + 210)/2) . cos ((x - 210° - x - 210°)/2)
= 2 sin x cos (-210)
= - 1/2√3 . 2 sin x

- 1/2 √3 . 2 sin x = 1/2 √3
sin x = -1/2
x = 210° dan 330°

HP = {7pi/6, 11pi/6}

jawabannya E