How much will 20 extra credit help you

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

Yoku is putting on sunscreen. he uses 2\text{ ml}2 ml to cover 50\text{ cm}^250 cm 2 of his skin. he wants to know how many milliliters of sunscreen (c)(c) he needs to cover 325\text{ cm}^2325 cm 2 of his skin. how many milliliters of sunscreen does yoku need to cover 325 \text{ cm}^2325 cm 2 of his skin?

What is the reflection image of (5,-3) across the line y = -x?