I need help with this

Evaluate cos2θ for cosθ = square root of 3/2

The candy store is having a 30% off sale. emma is going to buy $7.50 worth of candy.how much will she pay after the discount

Becca wants to mix fruit juice and soda to make a punch. she can buy fruit juice for $3 a gallon and soda for $4 a gallon. if she wants to make 28 gallons of punch at a cost of $3.25 a gallon, how many gallons of fruit juice and how many gallons of soda should she buy?