HELP ME SOLVE THE LAST ONE, IF THEYRE ALL WRONG CORRECT THEM, TY

Refer to interactive solution 17.45 to review a method by which this problem can be solved. the fundamental frequencies of two air columns are the same. column a is open at both ends, while column b is open at only one end. the length of column a is 0.504 m. what is the length of column b?

Aperpendicular bisector, cd is drawn through point con ab if the coordinates of point a are (-3, 2) and the coordinates of point b are (7,6), the x-intercept of cd is point lies on cd.

1.two more than the quotient of a number and 6 is equal to 7 use the c for the unknown number translate the sentence into an equation