Answer:
The length of the floor is [tex](15x^{2}+4x)\ ft[/tex]
Step-by-step explanation:
we know that
The area of a rectangle ( classroom floor) is equal to
[tex]A=LW[/tex]
in this problem we have
[tex]A=(30x^{3}+8x^{2})\ ft^{2}[/tex]
[tex]W=2x\ ft[/tex]
substitute in the formula and solve for L
[tex](30x^{3}+8x^{2})=2x(L)[/tex]
Divide by 2x both sides
[tex]L=(15x^{2}+4x)\ ft[/tex]
