Solve for x in the proportion

x -5
------ = -----
2x+5 x

A. x=5
B. x=15
C. x=-25
D. x=-5

Question

Solve for x in the proportion 

    x             -5
------  =  -----
 2x+5           x

A. x=5
B. x=15
C. x=-25
D. x=-5

parthkohli · Answer

Cross multiply.

parthkohli · Answer

$\Large \color{MidnightBlue}{\Rightarrow x^2 = -5(2x + 5) }$
$\Large \color{MidnightBlue}{\Rightarrow x^2 = -10x - 25 }$

parthkohli · Answer

This makes a quadratic equation.

parthkohli · Answer

Do you know how to solve them?

parthkohli · Answer

Well here I give the formula.

$\Large \color{MidnightBlue}{\Rightarrow x = {-b \pm \sqrt{b^2 - 4ac} \over 2a} }$

anonymous · Answer

Thanks for the hints, but can you just give me the answer? I'm kind of in a hurry to get the answer...

parthkohli · Answer

Hmm if you're in a hurry and you want the answer, then I don't recommend this site to you. Use wolfram.

radar · Answer

$$x ^{2}+10x+25=0$$ Same equation but in a more familiare form

parthkohli · Answer

This is actually a perfect square, so you have only one solution.

radar · Answer

Note that it will factor, making an easy solution.

anonymous · Answer

So... what is it?

radar · Answer

(x+5)(x+5)=0      There it is factored for you.