Plz
what is a perfect square trinomials?

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

Juanita wade's new car has an msrp of $28,902.11 including title and processing fees. the premier package which includes surround sound and dvd player costs three times the amount of the in-style package which includes leather seats and select wheels. the total cost of her new car was $34,290.08 which included the 6.5% sales tax. find the cost of the premier package to the nearest cent.

Arectangular courtyard is 12 feet long and 8 feet wide. a tile is 2 feet long and 2 feet wide. how many tiles are needed to cover the courtyard?