Algebra
Erik wants the cubby bookshelf to have a total height of
[tex]H=x^2-6x-27[/tex]And the total width of
[tex]W=x^2+4x+3[/tex]We are given each cubby hole in the bookshelf will have a height of
[tex]h=x+1[/tex]The number of cubbies that the bookshelf will be can be obtained by dividing the total height by the individual height:
[tex]n=\frac{H}{h}=\frac{x^2-6x-27}{x+1}[/tex]That is the required rational expression for the height.