I’m actually begging guys please help me

For f(x)=2x+1 and g(x)= x^2 -7, find (f•g)(x)

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?

Which simplifys to a+ b? a-(1-b)+1 -(1-a)-b+1 (a--1) -1)+1