Plzz help 12-13 points

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

Anyone know? is appreciated! will mark brainliest if correct!

In right ∆abc shown below, the midpoint of hypotenuse ac is located at d and segment bd is drawn.if ab = 12 and bc = 16, then explain why bd = 10. hint: consider what you know about the diagonals of a rectangle.