please explain step by step how to do the problem & how you got single variable so i am able to understand when i do it myself, i rate! thank you!

13 A 10-year maturity, 9% coupon bond paying coupons semiannually is callable in five years at a call price of $1,100. The bond currently sells at a yield to maturity of 7% (3.5% per half-year). a) (8 points) Calulate the bond's current price. b) (8 points) Calulate the bond's yield to call