Who go sum lit pa. dlet that i can join cuz im bred aa thank yoouuu

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

How is working backward similar to solving an equation?

Find the area of an equilateral triangle with a side of 6 inches