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a,\(\frac{1}{8}>0>\frac{-3}{8}\)
\(\Rightarrow\frac{1}{8}>\frac{-3}{8}\)
b,\(2\frac{1}{2}=\frac{5}{2}\)
\(\frac{-3}{7}< 0< \frac{5}{2}\)
\(\Rightarrow\frac{-3}{7}< \frac{5}{2}\)
\(\Rightarrow\frac{-3}{7}< 2\frac{1}{2}\)
c,\(-3,9< 0< 0,1\)
\(\Rightarrow-3,9< 0,1\)
d,\(-2,3< 0< 3,2\)
\(\Rightarrow-2,3< 3,2\)
Chúc bạn học giỏi nha!!!
K cho mik vs nhé
Ta thấy:
a) -3/8 < 0 < 1/8
=> -3/8 < 1/8
b) -3/7 < 0 < 1/2
=> -3/7 < 1/2
c) -3,9 < 0 < 0,1
=> -3,9 < 0,1
d) -2,3 < 0 < 3,2
=> -2,3 < 3,2
Ngoài ra bn có thể lm cách quy đồng tử hoặc mẫu
1
A)Z ; Q B)Q C)Q D)Q E)N ; Z ; Q
2
A)> B)< C)< D)<
Bài 1:
a) \(\mathbb{Z}\)
b) \(\mathbb{Q}\)
c) \(\mathbb{Q}\)
d) \(\mathbb{Z}\)
e) \(\mathbb{N}\)
Bài 2:
a) Ta thấy: \(\frac{1}{8}>0; \frac{-3}{8}< 0\) \(\Rightarrow \frac{1}{8}> \frac{-3}{8}\)
b) \(\frac{-3}{7}< 0; 2\frac{1}{2}>0\Rightarrow \frac{-3}{7}< 2\frac{1}{2}\)
c) \(-3,9< 0< 0,1\)
d) \(-2,3< 0< 3,2\)
c)\(\left|2x+3\right|=x+2\)
Đk:\(x+2\ge0\Rightarrow x\ge-2\)
TH1:2x+3=x+2
\(\Rightarrow2x-x=2-3\)
\(\Rightarrow x=-1\)(Thỏa mãn đk )
TH2:2x+3=-x-2
\(\Rightarrow2x+x=-2+3\)
\(\Rightarrow3x=1\)
\(\Rightarrow x=\frac{1}{3}\)(Thỏa mãn đk)
Vậy x=-1 hoặc x=1/3
a) \(10,\left(3\right)+0,\left(4\right)-8,\left(6\right)\)
\(=\frac{31}{3}+\frac{4}{9}-\frac{26}{3}\)
\(=\left(\frac{31}{3}-\frac{26}{3}\right)+\frac{4}{9}=\frac{5}{3}+\frac{4}{9}=\frac{15}{9}+\frac{4}{9}=\frac{19}{9}\)
b) \(\left[12,\left(1\right)-2,3\left(6\right)\right]:4,\left(21\right)\)
\(=\left[\frac{109}{9}-\frac{71}{30}\right]:\frac{139}{33}\)
\(=-\frac{52}{45}:\frac{139}{33}=-\frac{52}{45}\cdot\frac{33}{139}=-\frac{572}{2085}\)(số xấu quá)
c) \(3\frac{1}{2}\cdot\frac{4}{49}-\left[2,\left(4\right)\cdot2\frac{5}{11}\right]:\frac{-42}{53}\)
\(=\frac{7}{2}\cdot\frac{4}{49}-\left[\frac{22}{9}\cdot\frac{27}{11}\right]\cdot\frac{-53}{42}\)
\(=\frac{2}{7}-6\cdot\left(-\frac{53}{42}\right)=\frac{2}{7}-\left(-\frac{53}{7}\right)=\frac{2}{7}+\frac{53}{7}=\frac{55}{7}\)
a) (2x-1)\(^2\)+\(\left|2y-x\right|\)=0
Vì (2x-1)\(^2\)\(\ge\)0 với mọi x
\(\left|2y-x\right|\)\(\ge\)0 với mọi y
\(\Rightarrow\)\(\left\{\begin{matrix}2x-1=0\\2y-x=0\end{matrix}\right.\)\(\Rightarrow\)\(\left\{\begin{matrix}x=\frac{1}{2}\\2y-\frac{1}{2}=0\end{matrix}\right.\)\(\Rightarrow\)\(\left\{\begin{matrix}x=\frac{1}{2}\\y=\frac{1}{4}\end{matrix}\right.\)
Vậy .....
b)\(\left|x-\frac{1}{3}\right|\)+\(\frac{4}{5}\)=\(\frac{14}{5}\)
\(\Rightarrow\)\(\left|x-\frac{1}{3}\right|\)=2
\(\Rightarrow\)\(\left[\begin{matrix}x-\frac{1}{3}=2\\x-\frac{1}{3}=-2\end{matrix}\right.\)\(\Rightarrow\)\(\left[\begin{matrix}x=\frac{7}{3}\\x=\frac{-5}{3}\end{matrix}\right.\)
Vậy ....
a , 4,6
b , 0
b , - 1,4
a) [ 2,3 ] - [ - 2,3 ] = 2,3 + 2,3 = 4,6
b) [ 3,2 ] + [ - 3,2 ] = 3,2 - 3,2 = 0
c) [ - 5,4 ] - [ \(-\frac{2}{5}\)] = - 5,4 + 0,4 = - 5