Answer: [tex]5x^{2}+45x[/tex]
Step-by-step explanation:
1. First, you must calculate the area of the football field. It is a rectangle, therefore, multiply the lenght by the width to calculate the area:
[tex]Area=lenght*width\\Area=(10x^{2}+90x)5x^{2}\\Area=50x^{4}+450x^{3}[/tex]
2. Then, divide this area by the area covered by a wheelbarrow full of dirt.
[tex]x[/tex]: number of wheelbarrows full of dirt needed for the field.
[tex]x=\frac{50x^{4}+450x^{3}}{10x^{2}}=5x^{2}+45x[/tex]
