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a. 6 và 5/3 + 7 và 13/8 +3 và 1/3- 4 và 5/8
=23/3+69/8+4/3-37/8
=391/24+4/3+37/8=141/8-37/8=103/8
b.=(27/5+69/11)-(17/5-52/11)
=642/55+73/55=13
6 2/7 + 7 3/5 + 8 6/9 + 9 1/4 + 2/5 + 5/7 + 1/3 x 3/4 + 1967
= 44/7 + 38/5 + 78/9 + 37/4 + 2/5 + 5/7 + 1/3 + 1967
= ( 44/7 + 5/7 ) + ( 38/5 + 2/5 ) + ( 26/3 + 1/3 ) + ( 37/4 + 3/4 ) +1967
= 7 + 8 + 9 + 10 + 1967
= 15 + 9 + 10 + 1967
= 24 + 10 + 1967
= 34 + 1967
= 2001
A = (1 - \(\frac{1}{2}\)) x (1 - \(\frac{1}{3}\)) x (1 - \(\frac{1}{4}\)) x (1 - \(\frac{1}{5}\)) x ... x (1 - \(\frac{1}{2014}\)) x (1 - \(\frac{1}{2015}\))
A = \(\frac{1}{2}\)x \(\frac{2}{3}\) x \(\frac{3}{4}\) x \(\frac{4}{5}\) x ... x \(\frac{2013}{2014}\)x \(\frac{2014}{2015}\)
A = \(\frac{1x2x3x4x...x2013x2014}{2x3x4x5x...x2014x2015}\)
A = \(\frac{1}{2015}\)
Vậy A = \(\frac{1}{2015}\)
~~~
Tìm \(x\):
a; \(x\) + 35,2 = [25,6 + 3,14] x 3
\(x+\) 35,2 = 28,74 x 3
\(x\) + 35,2 = 86,22
\(x\) = 86,22 - 35,2
\(x\) = 51,02
b; \(\frac{17}{5}\) : \(x\) = \(\frac{34}{5}\) : \(\frac43\)
\(\frac{17}{5}\) : \(x\) = \(\frac{34}{5}\) x \(\frac34\)
\(\frac{17}{5}\) : \(x\) = \(\) \(\frac{51}{10}\)
\(x\) = \(\frac{17}{5}\) : \(\frac{51}{10}\)
\(x\) = \(\frac{17}{5}\) x \(\frac{10}{51}\)
\(x\) = \(\frac23\)
c; [\(x\) - \(\frac12\)] x \(\frac53\) = \(\frac74\) - \(\frac12\)
[\(x\) - \(\frac12\)] x \(\frac53\) = \(\frac74-\frac24\)
[\(x-\frac12\)] x \(\frac53\) = \(\frac54\)
\(x-\frac12\) = \(\frac54\) : \(\frac53\)
\(x-\frac12\) = \(\frac54\) x \(\frac35\)
\(x\) - \(\frac12\) = \(\frac34\)
\(x=\frac34+\frac12\)
\(x=\frac34+\frac24\)
\(x=\) \(\frac54\)
d; [72 - 4 x \(x\)] : 9 = 4
72 - 4 x \(x\) = 4 x 9
72 - 4 x \(x\) = 36
4 x \(x\) = 72 - 36
4 x \(x\) = 36
\(x\) = 36 : 4
\(x\) = 9
\(\left(5-\frac{23}{7}\right)×\frac{63}{24}+\frac{11}{9}:\frac{2}{3}\)
\(=\frac{12}{7}×\frac{63}{24}+\frac{11}{9}:\frac{2}{3}\)
\(=\frac{9}{2}+\frac{11}{9}:\frac{2}{3}\)
\(=\frac{9}{2}+\frac{11}{6}\)
\(=\frac{19}{3}\)
\(15+15\cdot2+7\cdot15-100\)
\(=15+30+105-100\)
\(=150-100\)
\(=50\)
15 + 15 * 2 + 7 * 15 - 100
= 15 * ( 1+2+7) - 100
= 15*10-10*10
= (15-10) * 10
= 5 * 10
= 50
\(\frac29\) : \(\frac29\) x \(\frac12\)
= \(\frac29\) x \(\frac92\) x \(\frac12\)
= 1 x \(\frac12\)
= \(\frac12\)
\(\frac27\) : \(\frac23\) - \(\frac17\)
= \(\frac27\times\frac32\) - \(\frac17\)
= \(\frac37\) - \(\frac17\)
= \(\frac27\)
\(\frac23\) x \(\frac34\) x \(\frac45\) : \(\frac15\)
= \(\frac12\) x \(\frac45\) : \(\frac15\)
= \(\frac25\) : \(\frac15\)
= \(\frac25\) x \(\frac51\)
= \(\frac21\)
= 2
a) 2014 x 7 + 2 x 2014 + 2014
= 2014 x ( 7+2+1)
= 2014 x 10 = 20140
b) 4/7 - 9/7 - 2/7 x 4
= (4-9-2) / 2 x 4
= (-7) : 2 x 4 = -7 x 2 = -14
a. 2014x7+2x2014+2014
=2014x7+2x2014+2014x1
=2014x(2+7+1)
=2014x10
=20140