Math question

[c0d0ps]

(2x+1)^2+(x+2)^2-x(5x+13)=0

"complete the equation" aka "What is X?"

 

What I have done so far is:

4x^2 + 4x + 1 + x^2 + 4x + 4 - 5x^2 + 13x=0

5x^2 + 8x + 5 - 5x^2+13x=21x+5=0
21x=0-5= -5

Then I brain freeze because I know it's wrong but can't see it any other way ..

 

The answer is supposed to be X=1 but I don't know how to get there.

 

Edit: The question has been answered, I have completed the equation/test correctly now.

Therefor I will stop following the thread.

[ilikemacandpc]

In your first step, shouldn't it be  - 13x? emphasis on the negative sign

[werto165]

-13x!!!!!!!!!!!!!!!!!!!!!!

 

so 8x-13x = -5x 

-5x = -5 

x=1

[Xaring]

http://www.wolframalpha.com/input/?i=%282x%2B1%29%5E2%2B%28x%2B2%29%5E2-x%285x%2B13%29%3D0

 

Click step by step solution

[c0d0ps]

In your first step, shouldn't it be  - 13x? emphasis on the negative sign

 

 

-13x!!!!!!!!!!!!!!!!!!!!!!

That might be it ..

I'll check.

Thanks.

[failblox]

http://i.imgur.com/j4CVxCo.jpg

 

In the first line it's supposed to be -13x, not +13x. As you can see in the photo above, the x² terms cancel out (4x²+x²-5x²=0), leaving an equation that is only degree one.

[c0d0ps]

http://www.wolframalpha.com/input/?i=%282x%2B1%29%5E2%2B%28x%2B2%29%5E2-x%285x%2B13%29%3D0

 

Click step by step solution

I don't see it explaining it anything.

 

Edit: After I changed it to -13x instead of +13x it made sense so it helped a little bit ^^

[c0d0ps]

http://i.imgur.com/j4CVxCo.jpg

 

In the first line it's supposed to be -13x, not +13x. As you can see in the photo above, the x² terms cancel out (4x²+x²-5x²=0), leaving an equation that is only degree one.

Yeah, it makes sense now thanks.