A study found a significant relationship among a persons years of experience on a particular job x1,

Question:

A study found a significant relationship among a person’s years of experience on a particular job x1, the number of workdays missed per month x2, and the person’s age y. The regression equation is y’ = 12.8 + 2.09x1 + 0.423x2. Predict a person’s age if he or she has been employed for 4 years and has missed 2 workdays a month.