a 150 g sample of ice at -8 degrees C is added to 500 g water at 75 degrees C in an insulated container. What is the final temperature after thermal equilibrium is reached?

i got an answer of 13.42 degrees by doing
(4.18)(x-75)(500g H2O)=(4.18)(x-(-8))(150 g H2O) and then solving for x but the answer I got was wrong so can someone explain to me the correct way to do it please?

Question

a 150 g sample of ice at -8 degrees C is added to 500 g water at 75 degrees C in an insulated container. What is the final temperature after thermal equilibrium is reached? 

i got an answer of 13.42 degrees by doing
(4.18)(x-75)(500g H2O)=(4.18)(x-(-8))(150 g H2O)   and then solving for x but the answer I got was wrong so can someone explain to me the correct way to do it please?