I need help please.

Solve the flooring system by the elimination system

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

You are on a cycling trip around europe with friends. you check the weather forecast for the first week. these are the temperatures for the week. sun mon tues wed thurs fri sat 16°c 20°c 24°c 28°c 28°c 23°c 15°c what is the mean temperature forecast for the week?

Can someone me do math because i am having a breakdown rn because i don’t get it