1.Tìm x, biết:
\(\left(x+\frac{1}{2}\right).\left(\frac{2}{3}-2x\right)=0\)
2.Tính hợp lí:
a.47.(23+50)-23.(47+50)
b.\(\frac{3}{6}+\frac{3}{30}+\frac{3}{70}+\frac{3}{126}+....+\frac{3}{286}\)
Những câu hỏi liên quan
Tìm x biết :
a)\(\frac{2}{3}x-50\%x-\left(-\frac{4}{5}\right):1\frac{3}{5}=-0,12\)\(+1\frac{3}{25}\)
b)\(\left(-1\frac{1}{6}+\frac{2}{3}-\frac{3}{4}\right):x+\left(-1\frac{11}{12}\right).1\frac{21}{23}=-6\frac{1}{3}\)
c)\(50\%x-\frac{1}{3}x-\left(\frac{-2}{3}\right)^2.\left(-1\frac{1}{8}\right)=-119\frac{3}{4}+120\frac{5}{6}\)
Câu 6. Giải các phương trình sau:
a, x+frac{2x+frac{x-1}{5}}{3}1-frac{3x-frac{1-2x}{3}}{5}; b, frac{3x-1-frac{x-1}{2}}{3}-frac{2x+frac{1-2x}{3}}{2}frac{frac{3x-1}{2}}{5}-6
Câu 7. Giải các phương trình sau:
a, frac{x-23}{24}+frac{x-23}{25}frac{x-23}{26}+frac{x-23}{27}; b, left(frac{x+2}{98}+1right)+left(frac{x+3}{97}+1right)left(frac{x+4+++}{96}+1right)+left(frac{x+5}{95}+1right)
c, frac{x+1}{2004}+frac{x+2}{2003}frac{x+3}{2002}+frac{x+4}{2001}...
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Câu 6. Giải các phương trình sau:
a, x+\(\frac{2x+\frac{x-1}{5}}{3}=1-\frac{3x-\frac{1-2x}{3}}{5}\); b, \(\frac{3x-1-\frac{x-1}{2}}{3}-\frac{2x+\frac{1-2x}{3}}{2}=\frac{\frac{3x-1}{2}}{5}-6\)
Câu 7. Giải các phương trình sau:
a, \(\frac{x-23}{24}+\frac{x-23}{25}=\frac{x-23}{26}+\frac{x-23}{27}\); b, \(\left(\frac{x+2}{98}+1\right)+\left(\frac{x+3}{97}+1\right)=\left(\frac{x+4+++==}{96}+1\right)+\left(\frac{x+5}{95}+1\right)\)
c, \(\frac{x+1}{2004}+\frac{x+2}{2003}=\frac{x+3}{2002}+\frac{x+4}{2001}\); d, \(\frac{201-6}{99}+\frac{203-6}{97}=\frac{205-x}{95}+3=0\)
e, \(\frac{x-45}{55}+\frac{x-47}{53}=\frac{x-55}{45}+\frac{x-53}{47}\); f, \(\frac{x+1}{9}+\frac{x+2}{8}=\frac{x+3}{7}+\frac{x+4}{6}\)
g, \(\frac{x+2}{98}+\frac{x+4}{96}=\frac{x+6}{94}+\frac{x+8}{92}\); h, \(\frac{2-x}{2002}-1=\frac{1-x}{2003}-\frac{x}{2004}\)
i, \(\frac{x^2-10x-29}{1971}+\frac{x^2-10x-27}{1973}=\frac{x^2-10x-1971}{29}+\frac{x^2-10x-1973}{27}\);
Câu 6 :
a, Ta có : \(x+\frac{2x+\frac{x-1}{5}}{3}=1-\frac{3x-\frac{1-2x}{3}}{5}\)
=> \(\frac{15x}{15}+\frac{5\left(2x+\frac{x-1}{5}\right)}{15}=\frac{15}{15}-\frac{3\left(3x-\frac{1-2x}{3}\right)}{15}\)
=> \(15x+5\left(2x+\frac{x-1}{5}\right)=15-3\left(3x-\frac{1-2x}{3}\right)\)
=> \(15x+10x+\frac{5\left(x-1\right)}{5}=15-9x+\frac{3\left(1-2x\right)}{3}\)
=> \(15x+10x+x-1=15-9x+1-2x\)
=> \(15x+10x+x-1-15+9x-1+2x=0\)
=> \(37x-17=0\)
=> \(x=\frac{17}{37}\)
Vậy phương trình trên có nghiệm là \(S=\left\{\frac{17}{37}\right\}\)
Bài 7 :
a, Ta có : \(\frac{x-23}{24}+\frac{x-23}{25}=\frac{x-23}{26}+\frac{x-23}{27}\)
=> \(\frac{x-23}{24}+\frac{x-23}{25}-\frac{x-23}{26}-\frac{x-23}{27}=0\)
=> \(\left(x-23\right)\left(\frac{1}{24}+\frac{1}{25}-\frac{1}{26}-\frac{1}{27}\right)=0\)
=> \(x-23=0\)
=> \(x=23\)
Vậy phương trình trên có nghiệm là \(S=\left\{23\right\}\)
c, Ta có : \(\frac{x+1}{2004}+\frac{x+2}{2003}=\frac{x+3}{2002}+\frac{x+4}{2001}\)
=> \(\frac{x+1}{2004}+1+\frac{x+2}{2003}+1=\frac{x+3}{2002}+1+\frac{x+4}{2001}+1\)
=> \(\frac{x+2005}{2004}+\frac{x+2005}{2003}=\frac{x+2005}{2002}+\frac{x+2005}{2001}\)
=> \(\frac{x+2005}{2004}+\frac{x+2005}{2003}-\frac{x+2005}{2002}-\frac{x+2005}{2001}=0\)
=> \(\left(x+2005\right)\left(\frac{1}{2004}+\frac{1}{2003}-\frac{1}{2002}-\frac{1}{2001}\right)=0\)
=> \(x+2005=0\)
=> \(x=-2005\)
Vậy phương trình trên có nghiệm là \(S=\left\{-2005\right\}\)
e, Ta có : \(\frac{x-45}{55}+\frac{x-47}{53}=\frac{x-55}{45}+\frac{x-53}{47}\)
=> \(\frac{x-45}{55}-1+\frac{x-47}{53}-1=\frac{x-55}{45}-1+\frac{x-53}{47}-1\)
=> \(\frac{x-100}{55}+\frac{x-100}{53}=\frac{x-100}{45}+\frac{x-100}{47}\)
=> \(\frac{x-100}{55}+\frac{x-100}{53}-\frac{x-100}{45}-\frac{x-100}{47}=0\)
=> \(\left(x-100\right)\left(\frac{1}{55}+\frac{1}{53}-\frac{1}{45}-\frac{1}{47}\right)=0\)
=> \(x-100=0\)
Vậy phương trình trên có nghiệm là \(S=\left\{100\right\}\)
1.Tìm x
a, \(-\frac{23}{5}.\frac{50}{23}\le x\le-\frac{13}{5}:\frac{23}{17}\)
b,\(-4\frac{1}{3}.\left(\frac{1}{2}-\frac{1}{6}\right)\le x\le-\frac{2}{3}\left(\frac{1}{3}-\frac{1}{2}-\frac{3}{4}\right)\)
c,\(\frac{x-1}{2014}+\frac{x-2}{2013}=\frac{x-3}{2012}+\frac{x-4}{2011}\)
bài 1: Tính bằng cách hợp lí1)frac{11}{3}:3frac{1}{3}-32)frac{5}{6}:frac{3}{52}-frac{5}{6}.47frac{1}{3}3)left(9frac{3}{4}:frac{26}{5}+frac{17}{5}.2frac{7}{34}right):left(-1frac{9}{16}right)4)left(frac{1}{2}-1right).left(frac{1}{3}-1right)...left(frac{1}{2002}-1right).left(frac{1}{2003}-1right)5)left(1-frac{1}{21}right).left(1-frac{1}{28}right).left(1-frac{1}{36}right)...left(1-frac{1}{1326}right)bài 2: tìm x :1)left(frac{2x}{3}-3right):left(-10right)frac{2}{5}2)left(x+frac{1}{5}right)left(x-frac...
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bài 1: Tính bằng cách hợp lí
1)\(\frac{11}{3}:3\frac{1}{3}-3\)
2)\(\frac{5}{6}:\frac{3}{52}-\frac{5}{6}.47\frac{1}{3}\)
3)\(\left(9\frac{3}{4}:\frac{26}{5}+\frac{17}{5}.2\frac{7}{34}\right):\left(-1\frac{9}{16}\right)\)
4)\(\left(\frac{1}{2}-1\right).\left(\frac{1}{3}-1\right)...\left(\frac{1}{2002}-1\right).\left(\frac{1}{2003}-1\right)\)
5)\(\left(1-\frac{1}{21}\right).\left(1-\frac{1}{28}\right).\left(1-\frac{1}{36}\right)...\left(1-\frac{1}{1326}\right)\)
bài 2: tìm x :
1)\(\left(\frac{2x}{3}-3\right):\left(-10\right)=\frac{2}{5}\)
2)\(\left(x+\frac{1}{5}\right)\left(x-\frac{2}{7}\right)< 0\)
mách mình với mấy cái kia là hỗn số nha
Bài 1:
1) \(\frac{11}{3}\): 3\(\frac{1}{3}\)- 3
= \(\frac{11}{3}\): \(\frac{10}{3}\)- 3
= \(\frac{11}{3}\). \(\frac{3}{10}\)- 3
= \(\frac{11}{10}\)- 3
= \(\frac{-19}{10}\)
2) \(\frac{5}{6}\): \(\frac{3}{52}\) - \(\frac{5}{6}\). 47\(\frac{1}{3}\)
= \(\frac{5}{6}\) . \(\frac{52}{3}\)- \(\frac{5}{6}\). 47\(\frac{1}{3}\)
= \(\frac{5}{6}\).(\(\frac{52}{3}\)- 47\(\frac{1}{3}\))
= \(\frac{5}{6}\).( -30)
= -25
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1) giải phương trình: a) left(2x+3right)left(frac{3x+8}{2-7x}+1right)left(x+5right)left(frac{3x+8}{2-7x}+1right)b) frac{7x+10}{x+1}left(x^2-x-2right)-frac{7x+10}{x+1}left(2x^2-3x-5right)0c) frac{2x+5}{x+3}+1frac{4}{x^2+2x-3}-frac{3x-1}{1-x}d) frac{13}{2x^2+x-21}+frac{1}{2x+7}+frac{6}{9-x^2}0e) frac{x-49}{50}+frac{x-50}{49}frac{49}{x-50}+frac{50}{x-49}f) frac{1+frac{x}{x+3}}{1-frac{x}{x+3}}3
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1) giải phương trình:
a) \(\left(2x+3\right)\left(\frac{3x+8}{2-7x}+1\right)=\left(x+5\right)\left(\frac{3x+8}{2-7x}+1\right)\)
b) \(\frac{7x+10}{x+1}\left(x^2-x-2\right)-\frac{7x+10}{x+1}\left(2x^2-3x-5\right)=0\)
c) \(\frac{2x+5}{x+3}+1=\frac{4}{x^2+2x-3}-\frac{3x-1}{1-x}\)
d) \(\frac{13}{2x^2+x-21}+\frac{1}{2x+7}+\frac{6}{9-x^2}=0\)
e) \(\frac{x-49}{50}+\frac{x-50}{49}=\frac{49}{x-50}+\frac{50}{x-49}\)
f) \(\frac{1+\frac{x}{x+3}}{1-\frac{x}{x+3}}=3\)
a) left|2xfrac{1}{3}right|+frac{5}{6}1b)frac{17}{2}-left|2x-frac{3}{4}right|-frac{7}{4}c) frac{2}{3}x-frac{3}{2}xfrac{5}{12}d) frac{2}{5}+frac{3}{5}.left(3x-3,7right)-frac{53}{10}e) frac{7}{9}:left(2+frac{3}{4}xright)+frac{5}{9}frac{23}{27}f) left(2frac{4}{5}x-50right):frac{2}{3}51g)left(x+frac{1}{2}right).left(frac{2}{3}-2xright)0h)x.3frac{1}{4}+left(-frac{7}{6}right).x-1frac{2}{3}frac{5}{12}i)frac{6}{2}frac{-5+x}{15}k)frac{1}{21}+frac{1}{28}+frac{1}{36}+...+frac{2}{xleft(x+1right)}frac{2}{9}
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a) \(\left|2x\frac{1}{3}\right|+\frac{5}{6}=1\)
b)\(\frac{17}{2}-\left|2x-\frac{3}{4}\right|=-\frac{7}{4}\)
c) \(\frac{2}{3}x-\frac{3}{2}x=\frac{5}{12}\)
d) \(\frac{2}{5}+\frac{3}{5}.\left(3x-3,7\right)=-\frac{53}{10}\)
e) \(\frac{7}{9}:\left(2+\frac{3}{4}x\right)+\frac{5}{9}=\frac{23}{27}\)
f) \(\left(2\frac{4}{5}x-50\right):\frac{2}{3}=51\)
g)\(\left(x+\frac{1}{2}\right).\left(\frac{2}{3}-2x\right)=0\)
h)\(x.3\frac{1}{4}+\left(-\frac{7}{6}\right).x-1\frac{2}{3}=\frac{5}{12}\)
i)\(\frac{6}{2}=\frac{-5+x}{15}\)
k)\(\frac{1}{21}+\frac{1}{28}+\frac{1}{36}+...+\frac{2}{x\left(x+1\right)}=\frac{2}{9}\)
Câu a \(\left|2x-\frac{1}{3}\right|+\frac{5}{6}=1\)
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g) \(\left(x+\frac{1}{2}\right)\left(\frac{2}{3}-2x\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x+\frac{1}{2}=0\\\frac{2}{3}-2x=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{-1}{2}\\x=\frac{1}{3}\end{cases}}\)
Vây \(x\in\left\{\frac{-1}{2};\frac{1}{3}\right\}\)
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i) \(\frac{6}{2}=\frac{-5+x}{15}\)
\(\Leftrightarrow3=\frac{x-5}{15}\)
\(\Leftrightarrow x-5=15.3\)
\(\Leftrightarrow x-5=45\)
\(\Leftrightarrow x=45+5\)
\(\Leftrightarrow x=50\)
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Xem thêm câu trả lời
Bài 4: Tính hợp lý
a) Aleft(left|frac{-3}{4}right|+left|frac{-2}{5}right|right):frac{3}{7}+left(frac{-3}{5}+left|frac{-1}{4}right|right):frac{3}{7}
b) B2frac{5}{23}-left(frac{-7}{9}right)-left|frac{-5}{23}right|+frac{12}{9}+left|-0,75right|
Bài 5 : Tìm x :
frac{11}{12}-left(frac{2}{5}+xright)left|frac{-2}{3}right|
b) left|xright|:left(frac{1}{9}-frac{2}{5}right)frac{-1}{2}
c) left(x-frac{1}{5}right).left(1frac{3}{5}+2xright)0
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Bài 4: Tính hợp lý
a) \(A=\left(\left|\frac{-3}{4}\right|+\left|\frac{-2}{5}\right|\right):\frac{3}{7}+\left(\frac{-3}{5}+\left|\frac{-1}{4}\right|\right):\frac{3}{7}\)
b) \(B=2\frac{5}{23}-\left(\frac{-7}{9}\right)-\left|\frac{-5}{23}\right|+\frac{12}{9}+\left|-0,75\right|\)
Bài 5 : Tìm x :
\(\frac{11}{12}-\left(\frac{2}{5}+x\right)=\left|\frac{-2}{3}\right|\)
b) \(\left|x\right|:\left(\frac{1}{9}-\frac{2}{5}\right)=\frac{-1}{2}\)
c) \(\left(x-\frac{1}{5}\right).\left(1\frac{3}{5}+2x\right)=0\)
Tìm số nguyên x biết: a) \(-4\frac{3}{5}.2\frac{4}{23}\le x\le-2\frac{3}{5}:1\frac{6}{15}\)
b) \(-4\frac{1}{3}.\left(\frac{1}{2}-\frac{1}{6}\right)\le x\le-\frac{2}{3}\left(\frac{1}{3}-\frac{1}{2}-\frac{3}{4}\right)\)
1. Tính hợp lí :
a) \(\frac{3}{4}-0,25-\left[\frac{7}{3}+\left(\frac{-9}{2}\right)\right]-\frac{5}{6}\)
b) 7 + \(\left(\frac{7}{12}-\frac{1}{2}+3\right)-\left(\frac{1}{12}+5\right)\)
2. Tìm các sô nguyên x biết:
\(\frac{3}{4}-\frac{5}{6}\le\frac{x}{12}< 1-\left(\frac{2}{3}-\frac{1}{4}\right)\)
Câu 1:
a)\(\frac{3}{4}-0,25-\left[\frac{7}{3}+\left(-\frac{9}{2}\right)\right]-\frac{5}{6}\)
\(=\frac{3}{4}-\frac{1}{4}-\frac{14}{6}+\frac{27}{6}-\frac{5}{6}\)
\(=\frac{1}{2}-\frac{4}{3}\)
\(=-\frac{5}{6}\)
b)\(7+\left(\frac{7}{12}-\frac{1}{2}+3\right)-\left(\frac{1}{12}+5\right)\)
\(=7+\frac{1}{12}+3-\frac{1}{12}-5\)
\(=5\)
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Câu 2:
\(\frac{3}{4}-\frac{5}{6}\le\frac{x}{12}< 1-\left(\frac{2}{3}-\frac{1}{4}\right)\)
\(-\frac{1}{12}\le\frac{x}{12}< 1-\frac{5}{12}\)
\(-\frac{1}{12}\le\frac{x}{12}< \frac{7}{12}\)
Vậy -1\(\le\)x<7
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