Answer:
[tex]Length = 6x^2 - 2x + 3[/tex]
Step-by-step explanation:
Given
[tex]Area = 42x^3 - 14x^2 + 21x[/tex]
[tex]Width = 7x[/tex]
Required
Determine the length of the aquarium
The area of a rectangular base is calculated as:
[tex]Area = Length * Width[/tex]
Substitute values for Area and Width
[tex]42x^3 - 14x^2 + 21x = Length * 7x[/tex]
Make Length the subject
[tex]Length = \frac{42x^3 - 14x^2 + 21x}{7x}[/tex]
Factorize the numerator
[tex]Length = \frac{7x(6x^2 - 2x + 3)}{7x}[/tex]
[tex]Length = 6x^2 - 2x + 3[/tex]