Question

Could someone please help me?
A person's rectanglar dog pen for his dog must have an area of 200 square feet. Also, the length must be 40 feet longer than the width. Find the dimensions of the pen.

Answer 1

Area= length*width
=x(x+40)
200=x(x=40) Multiply
\[200=x^2+40x\] Subtract 200 from both sides
\[x^2+40x-200=0\]

Answer 2

\[\frac{ -b \pm \sqrt{b^2-4ac} }{ 2a }\]
x=1 b=40 c=-200

Answer 3

\[\frac{ -(40)\pm \sqrt{(40)^2-4(1)(-200)} }{ 2(1) }\]

Answer 4

I'm not sure what to do next

Answer 5

@Atrineas

Answer 6

Ok so you would simplify everything by solving everything under the square root sign which would get you. . .?

Answer 7

You'd get 1200 wouldn't you?

Answer 8

1600+800
1600 because 40*40 is 1600 and 800 because a negative times a negative gets a positive
now whats 1600+800=?

Answer 9

2400

Answer 10

yes so that would making it look like. . .?

Answer 11

Make it look like**

Answer 12

\[\frac{(40)\pm \sqrt{2400} }{ 2(1) }\]

Answer 13

It's pretty easy from here. Just simplify.

Keep in mind that expression gives you x, which is the width. Don't forget to get the length.

Answer 14

Okay so the answer would be \[51\sqrt{2}?\]

Answer 15

@agent0smith

Answer 16

That doesn't look right at all. Show your work.

Answer 17

I did this all on a white board in math class I'm in English now so I don't know if I can redo it I don't even know how I got if this is right

Answer 18

\[\large \frac{(40)\pm \sqrt{2400} }{ 2(1) }\]all you have to do is simplify this. But whatever you did does not seem close.

Answer 19

Yeah I remember that but it'd become \[{ 40\sqrt{2400} }\]