I need Help please!!

Evaluate cos2θ for cosθ = square root of 3/2

At your job you're paid $50 per week plus $3 per sale at least how many saled do you need to make in order to have over $250

At a local museum, the total price for one adult and one child is $11. mrs. smith paid for herself and her three children. she spent $19. record the system of equations to be solved and then find the price of an adult and child ticket using either elimination or substitution.