Seventeen members of Tracy's family are going to an amusement park during the week of their family reunion. Adult tickets cost $32.50 each and child tickets cost $28 each. If the total cost for admission to the part is $530, how many adults went to the park?

So for z1 you would get 3.333833624065589 is the answer what I did was find cos of -70 and multiplied it by 7 that gave me 2.394141003279681.Next I did sin of -70 and that gave me .939692620785908. Last I added the both of them together and got the answer.