Dylan uses the expressions (x2 – 2x + 8) and (2x2 + 5x – 7) to represent the length and width of his bedroom. Which expression represents the area (lw) of Dylan’s room?

Respuesta :

Answer:

2[tex]x^{4}[/tex] + x³ - x² + 54x - 56

Step-by-step explanation:

Area (A) is calculated as

A = length × width

   = (x² - 2x + 8)(2x² + 5x - 7)

Each term in the second factor is multiplied by each term in the first factor, that is

x²(2x² + 5x - 7) - 2x(2x² + 5x - 7) + 8(2x² + 5x - 7) ← distribute all parenthesis

= 2[tex]x^{4}[/tex] + 5x³ - 7x² - 4x³ - 10x² + 14x + 16x² + 40x - 56 ← collect like terms, thus

A = 2[tex]x^{4}[/tex] +x³ - x² + 54x - 56

The expression which represents the area of Dylan’s room will be 2x⁴ - 7x³ - 21x² + 82x - 56.

What is the area?

The area is the space occupied by any shape, find out by multiplying its length and breadth.

We have,

Lenght =  (x² – 2x + 8)

and

Breadth = (2x² + 5x – 7)

Now, simplifying the above expressions,

(x² – 2x + 8)

It can be written as , Using middle term split method,

x² – 4x + 2x + 8

= x(x – 4) - 2(x - 4)

= (x – 4) (x - 2)

In the same way,

(2x² + 5x – 7)

= 2x² +7x  - 2x – 7

= x(2x +7)  - 1(2x + 7)

= (x - 1) (2x +7)

So,

So,

Using the area formula,

i.e.

Area = Length × Breadth

Area =  (x² – 2x + 8) ×  (2x² + 5x – 7) = (x – 4) (x - 2) (x - 1) (2x +7)

Now,

Area = 2x⁴ - 7x³ - 21x² + 82x - 56

Hence we can say that the expression which represents the area of Dylan’s room will be  2x⁴ - 7x³ - 21x² + 82x - 56.

To learn more about Area click here,

https://brainly.com/question/27683633

#SPJ2