How would you solve this using excel functions?

a$.$ Use the regression equation to predict the Salary of a quarterback with a $64\mathrm{.}5$ completion percentage, $22$ Touchdowns and is $39$ years old.

b$.$ Calculate and interpret the $95\%$ confidence interval for the mean salary for a quarterback with a $64\mathrm{.}5$ completion percentage, $22$ Touchdowns and is $39$ years old