Which expression is equivalent to sin(20°)cos(80°) – cos(20°)sin(80°)?

Use the identity sin(a − b) = sin(a)cos(b) − cos(a)sin(b). With a = 20° and b = 80°, the expression becomes sin(20° − 80°) = sin(−60°). Therefore, the equivalent expression is sin(−60°), choice A.

AI-written and checked against the verified answer.