Which expression is equivalent to sin(20°)cos(80°) – cos(20°)sin(80°)? sin(–60°)
cos(–60°)
cos(60°)
sin(60°)

How do i do this? i don’t understand

Find the roots of the equation below. x^2 - 6 + 9 = 0

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?