Show that the area of the rectangle is....

[mathlearn]

There's a rectangle which the length is x+1 and the breadth is x.

X is \(\displaystyle -1\pm\sqrt{11}\)

Show that the area is \(\displaystyle 11-\sqrt{11}\)

The workings I have done for far are below.

\(\displaystyle (-1\pm \sqrt{11})*(-1 \pm \sqrt{11} +1) \)

\(\displaystyle (-1\pm \sqrt{11})*( \pm \sqrt{11} ) \)

\(\displaystyle (-1\pm \sqrt{11})*( \pm \sqrt{11} ) \)

\(\displaystyle (-1\pm \sqrt{11})*( \pm \sqrt{11} ) \)

Where have I done wrong ? And the square root of the solution of the area you are asked to show is a negative. A comment here would be appreciated.

Many thanks :)

 

[MarkFL]

Measures cannot be negative, so we must have:

\(\displaystyle x=\sqrt{11}-1\)

And so:

\(\displaystyle x+1=\sqrt{11}\)

So, what is the area?

 

[mathlearn]

Measures cannot be negative, so we must have:

\(\displaystyle x=\sqrt{11}-1\)

And so:

\(\displaystyle x+1=\sqrt{11}\)

So, what is the area?

\(\displaystyle (-1+ \sqrt{11})*( + \sqrt{11} ) \)

\(\displaystyle - \sqrt{11}+ 11 \)

Correct? :)

 

[MarkFL]

Why would you multiply the expression representing the area by -1?

edit: I see you edited your post. :D

 

[mathlearn]

Why would you multiply the expression representing the area by -1?

edit: I see you edited your post. :D

(Party)(Party)(Happy) Thank you very much MarkFL