[toán 7 ] Tìm x

N

nhuquynhdat

$2009-|x-2009|=x$

$\leftrightarrow |x-2009|=2009-x$ đk: $x\le 2009$

$\leftrightarrow\left[\begin{matrix} x-2009=2009-x\\ x-2009=x-2009\end{matrix}\right.$

$\leftrightarrow\left[\begin{matrix} x=2009 (t/m)\\ 0x=0 (t/m)\end{matrix}\right.$
 
R

ronaldover7

2009−|x−2009|=x
\Rightarrow 2009=|x−2009|+x=|2009-x|+x \geq |2009-x+x|=2009
Đấu = xảy ra khi (2009-x)x \geq 0 \Rightarrow 2009 \geq x \geq 0
 
H

huynhbachkhoa23



Chuyển vế: $2009-x=|x-2009| \leftrightarrow x\le 2009$(mới nãy nhầm :D)

 
Last edited by a moderator:
You must log in or register to reply here.
Top Bottom