Evaluate each expression when a=1/3, b= 4 and c = 9

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

Which property was used to simplify the expression? 3c+9 +4c=3c+4c+9

Which best describes a central bank's primary goals? limiting inflation and reducing unemployment reducing unemployment and maintaining cash flow controlling stagflation and reducing unemployment managing credit and ensuring the money supply's liquidity