Plz help i need it for an exam

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅? a. sin (α -β) = sin α cos β – cos α sin β b. cos (α -β) = cos α cos β – sin α sin β c. cos (α -β) = cos α cos β + sin α sin β d. sin (α + β) = sin α cos β + cos α sin β

Why do interests rates on loans to be lower in a weak economy than in a strong one

Solve the equation -9p - 17 =10 a -3 b. 16 c. 18 d -16