Find the best answers to your questions at Westonci.ca, where experts and enthusiasts provide accurate, reliable information. Experience the ease of finding quick and accurate answers to your questions from professionals on our platform. Explore comprehensive solutions to your questions from a wide range of professionals on our user-friendly platform.

Dylan uses the expressions [tex](x^2 - 2x + 8)[/tex] and [tex](2x^2 + 5x - 7)[/tex] to represent the length and width of his bedroom. Which expression represents the area ( [tex]A[/tex] ) 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]


Sagot :

To determine the area of Dylan's bedroom, we need to multiply the expressions representing the length and width. Let's break it down step-by-step:

1. Identify the expressions:
- Length of the room: [tex]\( x^2 - 2x + 8 \)[/tex]
- Width of the room: [tex]\( 2x^2 + 5x - 7 \)[/tex]

2. Multiply the expressions:
To find the area, we use the distributive property (also known as the FOIL method for binomials) to multiply these polynomials:

[tex]\[ \begin{aligned} & (x^2 - 2x + 8)(2x^2 + 5x - 7) \\ & = x^2 \cdot (2x^2 + 5x - 7) - 2x \cdot (2x^2 + 5x - 7) + 8 \cdot (2x^2 + 5x - 7) \\ &= (x^2 \cdot 2x^2) + (x^2 \cdot 5x) + (x^2 \cdot -7) \\ &\quad - (2x \cdot 2x^2) - (2x \cdot 5x) - (2x \cdot -7) \\ &\quad + (8 \cdot 2x^2) + (8 \cdot 5x) + (8 \cdot -7) \\ &= 2x^4 + 5x^3 - 7x^2 - 4x^3 - 10x^2 + 14x + 16x^2 + 40x - 56 \end{aligned} \][/tex]

3. Combine like terms:
Now we combine the terms with the same degree:

[tex]\[ \begin{aligned} & 2x^4 + (5x^3 - 4x^3) + (-7x^2 - 10x^2 + 16x^2) + (14x + 40x) - 56 \\ & = 2x^4 + x^3 - x^2 + 54x - 56 \end{aligned} \][/tex]

4. Compare with options given:
After multiplying and simplifying the expression, the resulting polynomial is:

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

By examining the given options, we find that this expression matches exactly with one of the options provided:

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

Therefore, the expression that represents the area of Dylan's room is [tex]\(2x^4 + x^3 - x^2 + 54x - 56\)[/tex].