Please answer this I am in class I need the answer fast!

Issof claims that the scale factor is 1/2. which statement about his claim is correct

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

Yahir designs bracelets. he uses between 9 and 15 red and yellow beads in the ratio of 2 red bead to 5 yellow beads. drag the beads into the container to meet these requirements