If there is an int/integer in a array, and the same int/integer comes at the same spot, does it cancel each other out or does it reassing the value? (Java)

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?

Simplify this expression.2(10) + 2(x – 4) a. 2x + 16 b. x + 12 c. 2x + 12 d. x + 16

Solve the equation by completing the square. x^2+2x=17