Question

Bài 2 :

f) | 2x-1 | = | x+2 |

Answer 1

2x-1=-2-x hoặc 2x-1=x+2

+)2x-1=-2-x +)2x-1=x+2

3x=-1 x=3

x=\(-\dfrac{1}{3}\)

Vậy x=\(-\dfrac{1}{3}hoac3\)

Answer 2

\(\left|2x-1\right|=\left|x+2\right|\)

\(\Rightarrow\left[{}\begin{matrix}2x-1=x+2\\2x-1=-x-2\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}2x-x=1+2\Rightarrow x=3\\2x-1=-x-2\Rightarrow2x-1=-x\Rightarrow3x=1\Rightarrow x=\dfrac{1}{3}\end{matrix}\right.\)

Answer 3

| 2x-1 | = | x+2 |

nếu \(x\ge0\)thì

| 2x-1 | = | x+2 |

\(\Leftrightarrow2x-1=x+2\\ \Leftrightarrow2x-x-1-2=0\\ \Leftrightarrow x-3=0\\ \Leftrightarrow x=3\left(tmdk\right)\)

nếu x<0 thì

| 2x-1 | = | x+2 |

\(\Leftrightarrow1-2x=-x-2\\ \Leftrightarrow1-2x+x+2\\ \Leftrightarrow3-x=0\\ \Leftrightarrow x=3\left(ktmdk\right)\)

vậy nghiệm của phương trình là x=3