Answer:
[tex]A = 12n^4-15n^3-3n^2[/tex]
Step-by-step explanation:
The dimensions of a rectangle are length and breadth/width
Here we are given height . Assuming it to be one of the side of the rectangle , we will do the further calculation
Hence one side is
side 1 = [tex]3n^2[/tex]
And the other side is
Side 2 = [tex]4n^2-5n-1[/tex]
The area of rectangle = side 1 x side 2
[tex]A=3n^2 \times (4n^2-5n-1)[/tex]
[tex]A=3n^2 \times 4n^2-3n^2 \times 5n-3n^2 \times 1[/tex]
[tex]A=3 \times 4 \times n^2 \times n^2- 3 \times 5 \times n^2 \times n - 3n^2[/tex]
[tex]A = 12n^4-15n^3-3n^2[/tex]
Hence area can be given as expression
[tex]A = 12n^4-15n^3-3n^2[/tex]
