(42-33)-(-7+12) whats the answer

Can someone me with this problem i don't understand i need

The function show two sisters' savings account and the rate at which they plan to deposit money

The average daily maximum temperature for laura’s hometown can be modeled by the function f(x)=4.5sin(πx/6)+11.8 , where f(x) is the temperature in °c and x is the month. x = 0 corresponds to january.what is the average daily maximum temperature in may? round to the nearest tenth of a degree if needed.use 3.14 for π .