bantuin aku yaa jawab soal inii.. makasihh

jawab

cos x = 4/5
sin x = 3/5

sin 3x + sin x = 2 sin 2x cos x
= 2 (2 sin x cos x) (cos x)
= 4 sin x cos² x
= 4(3/5).(4/5)²
= 4 (3/5)(16/25)
= 192/125