I recommend u use the app called photomath. It works a lot.
Answer:
If you've learnt sin(A+B) = sinAcosB + cosAsinB,
sin(4u)
= sin(2u+2u)
= sin(2u)cos(2u) + cos(2u)sin(2u)
= 2 sin(2u) cos(2u).
Answer:
x = -3 is the answer. Writing this cause brainly requires a 20 character answer.