Hello :
sin<span>θ = 15/17
</span> use pythagorean identity : cos²θ +sin² θ = 1
cos²θ = 1 - sin² θ
cos²θ = 1-(15/17)²
cos²θ = 1- 225/289
cos²θ = 64/289
cos²θ = (8/17)²
cosθ = 8/17 or -8/17
Move all terms containing m to the left all other terms to the right 48+-6m=6m+-6m
48+-6m=0