15 decreased by twice a number algebraic expression?

What number should be added to the expression x^2+3x+ in order to create a perfect square trinomial? 3/2 3 9/4 9

John read the first 114 pages of a novel, which was 3 pages less than 1/3 of the novel. write an equation to determine the total number of pages (p)(p) in the novel.

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base