Idon’t understand how to find the value of x for this problem and i doing it right?

Aregression was run to determine if there is a relationship between hours of tv watched per day (x) and number of situps a person can do (y). the results of the regression were: y=ax+b a=-0.662 b=30.418 r2=0.703921 r=-0.839

What is the measure of ac? 5 units 13 units 26 units 39 units

In a school 2/3 of the students study a language of those who study a language 2/5 study french