Help help help please

Sam is a waiter at a local restaurant where he earns wages of $5 per hour sam figures that he also eams about $3 in tips for each person he serves sam works 6 hours on a particular day. if n represents the number of people sam serves that day, which of the following functions could sam use to figure ehis total earings for the do o a. en) = 30 o b. en) = 5n+ 18

Cos^2x+cos^2(120°+x)+cos^2(120°-x)i need this asap. pls me

Which of the following is best modeled using a linear equation y=ax+b, where a is less than 0?