Question

tim so nguyen x biet;

| x+9 |.2=10

Answer 1

|x + 9| . 2 = 10

\(\Rightarrow\) |x + 9| = 10 : 2

\(\Rightarrow\) |x + 9| = 5

\(\Rightarrow\)\(\left[\begin{matrix}x+9=5\\x+9=-5\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=5-9\\x=-5-9\end{matrix}\right.\Rightarrow}\left[\begin{matrix}x=-4\\x=-14\end{matrix}\right.\)

Vậy: x \(\in\) {-4; -14}

Answer 2

\(\left|x+9\right|.2=10\)

\(\left|x+9\right|=10:2\)

\(\left|x+9\right|=5\)

\(\Rightarrow\left\{\begin{matrix}x+9=5\\-\left(x+9\right)=5\end{matrix}\right.\Rightarrow\left\{\begin{matrix}x=-4\\-x-9=5\end{matrix}\right.\)

\(\Rightarrow\left\{\begin{matrix}x=-4\\-x=14\end{matrix}\right.\Rightarrow\left\{\begin{matrix}x=-4\\x=-14\end{matrix}\right.\)

Answer 3

l x+9 l.2=10

\(\Rightarrow\)lx+9l=10:2

\(\Rightarrow\)lx+9l=5 \(\Rightarrow\)\(\left\{\begin{matrix}x+9=5\\x+9=-5\end{matrix}\right.\) \(\Rightarrow\)\(\left\{\begin{matrix}x=-4\\x=-14\end{matrix}\right.\) vay x\(\in\){-4;-14}