Bài 1: Tìm x
a/ \(2\left|\frac{2}{3}-x\right|+\frac{1}{4}=\frac{3}{4}\)
\(2\left|\frac{2}{3}-x\right|=\frac{3}{4}-\frac{1}{4}\)
\(2\left|\frac{2}{3}-x\right|=\frac{1}{2}\)
\(\left|\frac{2}{3}-x\right|=\frac{1}{2}:2\)
\(\left|\frac{2}{3}-x\right|=\frac{1}{4}\)
\(\Rightarrow\frac{2}{3}-x=\frac{1}{4}\) hoặc \(\frac{2}{3}-x=\frac{-1}{4}\)
TH1: \(\frac{2}{3}-x=\frac{1}{4}\)
\(x=\frac{2}{3}-\frac{1}{4}\)
\(x=\frac{5}{12}\)
TH2: \(\frac{2}{3}-x=\frac{-1}{4}\)
\(x=\frac{2}{3}+\frac{1}{4}\)
\(x=\frac{11}{12}\)
Vậy \(x=\frac{5}{12}\) hoặc \(x=\frac{11}{12}\)
b/ \(\left(2x-1\right)^3=-8\)
\(\left(2x-1\right)^3=\left(-2\right)^3\)
\(\Rightarrow2x-1=-2\)
\(2x\) \(=-2+1\)
\(2x\) \(=-1\)
\(x\) \(=-1:2\)
\(x\) \(=\frac{-1}{2}\)
c/ \(2.\left|x-\frac{5}{7}\right|-\frac{2}{7}=\frac{1}{7}\)
\(2.\left|x-\frac{5}{7}\right|=\frac{1}{7}+\frac{2}{7}\)
\(2.\left|x-\frac{5}{7}\right|=\frac{3}{7}\)
\(\left|x-\frac{5}{7}\right|=\frac{3}{7}:2\)
\(\left|x-\frac{5}{7}\right|=\frac{3}{14}\)
\(\Rightarrow x-\frac{5}{7}=\frac{3}{14}\) hoặc \(x-\frac{5}{7}=\frac{-3}{14}\)
TH1: \(x-\frac{5}{7}=\frac{3}{14}\)
\(x\) \(=\frac{3}{14}+\frac{5}{7}\)
\(x\) \(=\frac{13}{14}\)
TH2: \(x-\frac{5}{7}=\frac{-3}{14}\)
\(x\) \(=\frac{-3}{14}+\frac{5}{7}\)
\(x\) \(=\frac{1}{2}\)
Vậy \(x=\frac{13}{14}\) hoặc \(x=\frac{1}{2}\)
a) 2 . \(\left|\frac{2}{3}-x\right|\) + \(\frac{1}{4}\) = \(\frac{3}{4}\)
2 . \(\left|\frac{2}{3}-x\right|\) = \(\frac{3}{4}\) - \(\frac{1}{4}\)
2 . \(\left|\frac{2}{3}-x\right|\) = \(\frac{2}{4}\) = \(\frac{1}{2}\)
\(\left|\frac{2}{3}-x\right|\) = \(\frac{1}{2}\) : 2
\(\left|\frac{2}{3}-x\right|\) = \(\frac{1}{4}\)
+) \(\frac{2}{3}\) - \(x\) = \(\frac{1}{4}\)
\(\Rightarrow\) \(x\) = \(\frac{5}{12}\)
+) \(\frac{2}{3}\) - \(x\) = \(\frac{-1}{4}\)
\(\Rightarrow\) \(x\) = \(\frac{11}{12}\)
b) (2\(x\) - 1)3 = -8
\(\Rightarrow\) (2\(x\) - 1)3 = (-2)3
\(\Rightarrow\) 2\(x\) - 1 = - 2
\(\Rightarrow\) 2\(x\) = -2+1 = -1
\(\Rightarrow\) \(x\) = \(\frac{-1}{2}\)
c) 2 . \(\left|x-\frac{5}{7}\right|\) - \(\frac{2}{7}\) = \(\frac{1}{7}\)
\(\Rightarrow\) 2 . \(\left|x-\frac{5}{7}\right|\) = \(\frac{1}{7}\) + \(\frac{2}{7}\) = \(\frac{3}{7}\)
\(\Rightarrow\) \(\left|x-\frac{5}{7}\right|\) = \(\frac{3}{7}\) : 2 = \(\frac{3}{14}\)
+) \(x\) - \(\frac{5}{7}\) = \(\frac{3}{14}\)
\(\Rightarrow\) \(x\) = \(\frac{13}{14}\)
+) \(x\) - \(\frac{5}{7}\) = \(\frac{-3}{14}\)
\(\Rightarrow\) \(x\) = \(\frac{1}{2}\)
Quá dễ,bn nên suy nghĩ trc khi hỏi đi,bài dễ tek này bn đi hỏi lm phụ thuộc vào người khác đấy
Những câu hỏi đơn giản thế này, bạn không nên đăng để nhường chỗ cho những câu hỏi khác
Nè, các bạn đừng vậy nhé, đâu phải ai cũng biết làm.
2*|2/3-x|=3/4-1/4
2*|2/3-x|=1/2
|2/3-x|=1/2/2
|2/3-x|=1/4
Suy ra: 2/3-x=1/4hoặc 2/3-x=-1/4
*2/3-x=1/4
x=2/3-1/4
x=5/12
*2/3-x=-1/4
x=2/3--1/4
x=11/12
