-Nếu \(x\ge2\)\(\Rightarrow\)\(\left|x-2\right|=x-2\)\(\Rightarrow\)\(\left|x-2\right|=x\)\(\Leftrightarrow\)\(x-2\)\(=x\)
\(\Leftrightarrow\)\(0x=2\)(Vô lý)
\(\Leftrightarrow\)\(x\in\varnothing\)
-Nếu \(x< 2\)\(\Rightarrow\left|x-2\right|=-\left(x-2\right)=2-x\)\(\Rightarrow\)\(\left|x-2\right|=x\Leftrightarrow2-x=x\)
\(\Leftrightarrow2x=2\)
\(\Leftrightarrow x=1\left(TMĐK\right)\)
Vậy x=1
Tìm GTNN của:
a) A = \(\left|x-1\right|+\left|x-2\right|+\left|x-3\right|+\left|x-4\right|+\left|x-5\right|\)
b) B = \(\left|x-1\right|+\left|x-2\right|+\left|x-3\right|+\left|x-4\right|+\left|x-5\right|+\left|x-6\right|\)
c) C = \(\left|x-1\right|+\left|x-2\right|+...+\left|x-n\right|\)( n là số lẻ )
d) D = \(\left|x-1\right|+\left|x-2\right|+...+\left|x-n\right|\)( n là số chẵn )
Cần giúp nhanh vs
Bài 1. Tìm x
a) \(\left|x+\dfrac{7}{4}\right|=\dfrac{1}{2}\)
b) \(\left|2x+1\right|-\dfrac{2}{5}=\dfrac{1}{3}\)
c) \(3x.\left(x+\dfrac{2}{3}\right)=0\)
d) \(x+\dfrac{1}{3}=\dfrac{2}{5}-\left(-\dfrac{1}{3}\right)\)
Bài 2. Tính nhanh
\(A=\dfrac{1}{100}-\dfrac{1}{100.99}-\dfrac{1}{99.98}-\dfrac{1}{98.97}-....-\dfrac{1}{3.2}-\dfrac{1}{2.1}\)
Tìm x : \(\dfrac{1}{x\left(x+1\right)}+\dfrac{1}{\left(x+1\right)\left(x+2\right)}+\dfrac{1}{\left(x+2\right)\left(x+3\right)}-\dfrac{1}{x}=\dfrac{1}{2010}\)
Tìm \(x\), biết :
a) \(\left|x\right|=2,5\)
b) \(\left|x\right|=-1,2\)
c) \(\left|x\right|+0,573=2\)
d) \(\left|x+\dfrac{1}{3}\right|-4=-1\)
Tìm \(x\) trong các tỉ lệ thức sau :
a) \(x:\left(-2,14\right)=\left(-3,12\right):1,2\)
b) \(2\dfrac{2}{3}:x=2\dfrac{1}{12}:\left(-0,06\right)\)
Tìm x biết
a)\(\left(3x+\dfrac{1}{3}\right)\left(x-\dfrac{1}{2}\right)=0\)
b)\(\left(x-\dfrac{3}{2}\right)\left(2x+1\right)>0\)
c)\(\left(2-x\right)\left(\dfrac{4}{5}-x\right)< 0\)
d)\(\left(x-\dfrac{4}{7}\right):\left(x+\dfrac{1}{2}\right)>0\)
e)\(2\left(x+1\right)-\dfrac{1}{3}.\left(x-1\right)=\dfrac{2}{3}\)
k)\(\left|4x-0,2\right|=0,2\)
a) \(\left|2x-1\right|+\left|x+8\right|=4x\)
b) \(\left(\sqrt{x+1}\right)\left(\sqrt{x-3}\right)=0\)
c) \(3^x+3^{x+2}=2430\)
a,P=\(\left(x-4\right)^{\left(x-5\right)^{\left(x-6\right)^{\left(x+6\right)^{\left(x+5\right)}}}}\). Hãy tính giá trị của P với x=7?
b, \(\left(x-1\right)^{x+2}=\left(x-1\right)^{x+4}\)
c, P=\(\left(-1\right)^n.\left(-1\right)^{2n+1}.\left(-1\right)^{n+1}\)
Tìm giá trị nhỏ nhất của biểu thức A=\(\left|x-1\right|+2\left|x-2\right|+3\left|x-3\right|+4\left|x-4\right|\)
\(\left|x-1\right|+\left|x-2\right|-3\left|x-3\right|=x-5\)
Tìm x
![ᵜB꙰Łąℭⓚ⒫Ĩ[̲̅n̲̅]k̫︵²⁰⁰⁷](https://hoc24.vn/images/avt/avt3093233_256by256.jpg)
