Today, everything at a store is on sale. the store offers a 20% discount. if the regular price of an item is x dollars, what is the discount price in dollars?

What are the sotions to the quadratic equation 9x^2=4

At the beginning of 1974/75,2 years a man invested #2000 in a bank at 12.5% compound interest, if it degree #650 at the end of each two years to pay his son's school fees, after payment of interest to pay his son's school fees, how much did he have left at the beginning of the 1978/79 school year?

If the value of cos330°is√3/2 then find cos 165°.