Dylan uses the expressions [tex]\left(x^2-2x+8\right)[/tex] and [tex]\left(2x^2+5x-7\right)[/tex] to represent the length and width of his bedroom. Which expression represents the area of Dylan's room?

A. [tex]2x^4-10x^2-56[/tex]
B. [tex]2x^4+10x^2+56[/tex]
C. [tex]2x^4+x^3-x^2+54x-56[/tex]
D. [tex]2x^4+9x^3+33x^2+54x+56[/tex]



Answer :

To solve this problem, we need to find the area of Dylan's room given the length and width expressions. The area of a rectangle is obtained by multiplying the length by the width.

1. The length of Dylan's room is given by [tex]\( L = x^2 - 2x + 8 \)[/tex].
2. The width of Dylan's room is given by [tex]\( W = 2x^2 + 5x - 7 \)[/tex].

To find the area, we need to multiply these two expressions:
[tex]\[ \text{Area} = L \times W \][/tex]
[tex]\[ \text{Area} = (x^2 - 2x + 8) \times (2x^2 + 5x - 7) \][/tex]

Upon performing the polynomial multiplication and combining like terms, the results yield:
[tex]\[ \text{Area} = 2x^4 + x^3 - x^2 + 54x - 56 \][/tex]

Hence, the expression that correctly represents the area of Dylan's room is:

[tex]\[ 2x^4 + x^3 - x^2 + 54x - 56 \][/tex]

So, the correct answer is:

[tex]\[ 2x^4 + x^3 - x^2 + 54x - 56 \][/tex]

This matches the third option provided in your question:

[tex]\[ \boxed{2 x^4 + x^3 - x^2 + 54 x - 56} \][/tex]