If 0≤β<2π, find all values of β that satisfy the equation cos(2β)=√3/2

Yao xin puts 3/10 liters of potting soil in each pot for planting flowers. she has 5 2\3 liters of potting soil. how many pots can yao xin fill?

2x+3y=12 x-y=6 solve the following system equations

Ametal rod needs to be 9 feet and 5.5 inches in length. the sections of the poles being used are each 1 foot and 10.5 inches long. how many 1ft 10.5in sections would be needed to complete the 9ft 5.5in metal rod? and how many inches of material will be left?