Ôn tập toán 7
Các câu hỏi tương tự
Tính
A= \(\dfrac{7}{1.2.3.4}+\dfrac{7}{2.3.4.5}+....+\dfrac{7}{98.99.100.101}\)
câu 1 tìm x biết
\((-1\dfrac{1}{5}+x)\div(-3\dfrac{3}{5})=\dfrac{-7}{4}+\dfrac{1}{4}\div\dfrac{1}{8}\)
\(\dfrac{5}{7}+\dfrac{2}{3}x=\dfrac{3}{10}\)
\(-\dfrac{22}{15}x+\dfrac{1}{3}=|-\dfrac{2}{3}+\dfrac{1}{5}|\)
Tìm số nguyên x biết:
a. \(-4\dfrac{3}{5}.2\dfrac{4}{23}\)<x<\(-2\dfrac{3}{5}:1\dfrac{6}{15}\) b. \(-4\dfrac{1}{3}.\left(\dfrac{1}{2}-\dfrac{1}{6}\right)< x< -\dfrac{2}{3}\left(\dfrac{1}{3}-\dfrac{1}{2}-\dfrac{3}{4}\right)\)
tìm X
-dfrac{1}{4}x+dfrac{2}{3}dfrac{5}{9}
xleft(dfrac{3}{5}right)^3dfrac{3}{5}
left|xright|+dfrac{1}{5}2-left(dfrac{2}{3}-dfrac{3}{4}right)
left(dfrac{-3}{4}right)^xdfrac{81}{256}
giúp mình vs
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tìm X
\(-\dfrac{1}{4}x+\dfrac{2}{3}=\dfrac{5}{9}\)
\(x\left(\dfrac{3}{5}\right)^3=\dfrac{3}{5}\)
\(\left|x\right|+\dfrac{1}{5}=2-\left(\dfrac{2}{3}-\dfrac{3}{4}\right)\)
\(\left(\dfrac{-3}{4}\right)^x=\dfrac{81}{256}\)
giúp mình vs
ĐỀ 1:
1. Tính:
a. dfrac{7}{23}left[left(dfrac{-8}{6}right)-dfrac{45}{18}right]
b. dfrac{1}{5}:dfrac{1}{10}-dfrac{1}{3}left(dfrac{6}{5}-dfrac{9}{4}right)
c. dfrac{3}{5}.left(dfrac{-8}{3}right)-dfrac{3}{5}:left(-6right)
d. dfrac{1}{2}left(dfrac{4}{3}+dfrac{2}{5}right)-dfrac{3}{4}left(dfrac{8}{9}+dfrac{16}{3}right)
e. dfrac{6}{7}:left(dfrac{3}{26}-dfrac{3}{13}right)+dfrac{6}{7}left(dfrac{1}{10}-dfrac{8}{5}right)
2. Tìm x, biết:
a. 1dfrac{2}{5}x+dfrac{3}{7}dfrac{4}{5}
b. |x - 1,5| 2
c. df...
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ĐỀ 1:
1. Tính:
a. \(\dfrac{7}{23}\left[\left(\dfrac{-8}{6}\right)-\dfrac{45}{18}\right]\)
b. \(\dfrac{1}{5}:\dfrac{1}{10}-\dfrac{1}{3}\left(\dfrac{6}{5}-\dfrac{9}{4}\right)\)
c. \(\dfrac{3}{5}.\left(\dfrac{-8}{3}\right)-\dfrac{3}{5}:\left(-6\right)\)
d. \(\dfrac{1}{2}\left(\dfrac{4}{3}+\dfrac{2}{5}\right)-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)\)
e. \(\dfrac{6}{7}:\left(\dfrac{3}{26}-\dfrac{3}{13}\right)+\dfrac{6}{7}\left(\dfrac{1}{10}-\dfrac{8}{5}\right)\)
2. Tìm x, biết:
a. \(1\dfrac{2}{5}x+\dfrac{3}{7}=\dfrac{4}{5}\)
b. |x - 1,5| = 2
c. \(\dfrac{4}{5}-\left|x-\dfrac{1}{6}\right|=\dfrac{2}{3}\)
d. 3x . 2x = 216
e. \(\dfrac{1}{2}\left(x-\dfrac{1}{3}\right)+\dfrac{-1}{2}=\dfrac{3}{4}\)
* Lm nhanh nha
Ths you <3
1. Tính :
a, \(A=\dfrac{\dfrac{1}{3}-\dfrac{5}{2}}{\dfrac{3}{4}-\dfrac{1}{2}}.\dfrac{\dfrac{5}{6}+\dfrac{7}{3}}{1-\dfrac{5}{6}}.\dfrac{\dfrac{-2}{5}+1}{\dfrac{2}{5}-1}\).
b, \(B=\dfrac{\dfrac{1}{3}-\dfrac{4}{5}}{\dfrac{1}{3}+\dfrac{4}{5}}.\dfrac{\dfrac{3}{4}-\dfrac{5}{3}}{\dfrac{3}{4}+\dfrac{5}{3}}:\dfrac{\dfrac{4}{5}-1}{1-\dfrac{2}{3}}\).
Tìm X:
1, dfrac{3}{5} - 4.|dfrac{1}{5} - dfrac{3}{4}.x | dfrac{1}{3}
2, |2dfrac{2}{9} - x| dfrac{1}{12} +dfrac{1}{20}+dfrac{1}{30}+dfrac{1}{42}+dfrac{1}{56}+dfrac{1}{72}
3, dfrac{1}{3}.x+dfrac{2}{5}.left(x-1right)0
4, 60% .x +dfrac{2}{3}.x dfrac{1}{3}.6dfrac{1}{3}
5, dfrac{x}{2.3}+dfrac{x}{3.4}+dfrac{x}{4.5}+....+dfrac{x}{49.50}1
Giúp mình nhé; lưu ý: dấu | ......| là giá trị tuyệt đối và các dấu chấm là nhân nhé!
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Tìm X:
1, \(\dfrac{3}{5}\) - 4.|\(\dfrac{1}{5}\) - \(\dfrac{3}{4}\).x | =\(\dfrac{1}{3}\)
2, |2\(\dfrac{2}{9}\) - x| =\(\dfrac{1}{12}\) +\(\dfrac{1}{20}\)+\(\dfrac{1}{30}+\dfrac{1}{42}+\dfrac{1}{56}+\dfrac{1}{72}\)
3, \(\dfrac{1}{3}.x+\dfrac{2}{5}.\left(x-1\right)=0\)
4, 60% .x +\(\dfrac{2}{3}\).x = \(\dfrac{1}{3}.6\dfrac{1}{3}\)
5, \(\dfrac{x}{2.3}+\dfrac{x}{3.4}+\dfrac{x}{4.5}+....+\dfrac{x}{49.50}=1\)
Giúp mình nhé; lưu ý: dấu "| ......|" là giá trị tuyệt đối và các dấu chấm là nhân nhé!
13 Tìm x, biết :
a) \(\dfrac{2}{3}x+4=-12\); b) \(\dfrac{3}{4}+\dfrac{1}{4}:x=-3\); c) \(\left|3x-5\right|=4\)
d) \(\dfrac{x+1}{10}+\dfrac{x+1}{11}+\dfrac{x+1}{12}=\dfrac{x+1}{13}+\dfrac{x+1}{14}\) ;
e) \(\dfrac{x+4}{2000}+\dfrac{x+3}{2001}=\dfrac{x+2}{2002}+\dfrac{x+1}{2003}\)
Chứng minh:
a. \(A=\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{8}-\dfrac{1}{16}+\dfrac{1}{32}-\dfrac{1}{64}< \dfrac{1}{3}\)
b.\(B=\dfrac{1}{3}-\dfrac{2}{3^2}+\dfrac{3}{3^3}-\dfrac{4}{3^4}+...+\dfrac{99}{3^{99}}< \dfrac{3}{16}\)
c. \(C=\dfrac{1}{41}+\dfrac{1}{42}+\dfrac{1}{43}+...+\dfrac{1}{79}+\dfrac{1}{80}>\dfrac{7}{12}\)