In the diagram below, ab is parallel to cd. what is the value of y?

Can someone me out here number 4 plz

If f(x)=x+7 and g(x)=1/x what is (fog)(x)

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?