Question

Which of the following represents the area of a rectangle whose length is x − 7 and whose width is x + 12?

Answer 1

(x-7)(x+12)
X^2 +12x-7x-84

x^2+5x-84. <- answer

Answer 2

`A=(x^(2)+5x-84)\ units^(2)`

Explanation:

we know that

The area of a rectangle is equal to

`A=WL`

where

W is the width of the rectangle

L is the length of the rectangle

In this problem we have

`L=(x-7)\ units`

`W=(x+12)\ units`

substitute

`A=(x-7)(x+12)\\A=x^(2)+12x-7x-84\\A=(x^(2)+5x-84)\ units^(2)`