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\(\frac{315}{316}\cdot\frac{316}{314}\cdot\frac{316}{315}\cdot\frac{317}{313}=\frac{315.316.316.317}{316.314.315.313}=\frac{1.1.316.317}{1.314.1.313}=\frac{100172}{98282}\)
Ta có : \(\frac{3}{2}\times\frac{4}{5}\times\frac{2}{3}\)
\(=\frac{3}{2}\times\frac{2}{3}\times\frac{4}{5}=1\times\frac{4}{5}\)
\(=\frac{4}{5}\)
\(\dfrac{9+x}{13-x}=\dfrac{5}{6}\\ \Rightarrow5\left(13-x\right)=6\left(9+x\right)\\ \Rightarrow65-5x=54+6x\\ \Rightarrow6x+5x=65-54\\ \Rightarrow11x=11\\ \Rightarrow x=1\)
Vậy x = 1
ĐKXĐ: \(x\ne13\)
\(\dfrac{9+x}{13-x}=\dfrac{5}{6}\)
\(\Leftrightarrow\dfrac{6\left(9+x\right)}{6\left(13-x\right)}=\dfrac{5\left(13-x\right)}{6\left(13-x\right)}\)
\(\Rightarrow6\left(9+x\right)=5\left(13-x\right)\)
\(\Leftrightarrow54+6x=65-5x\)
\(\Leftrightarrow6x+5x=65-54\)
\(\Leftrightarrow11x=11\)
\(\Leftrightarrow x=1\) (thỏa mãn ĐKXĐ)
\(9+\frac{x}{13}-x=\frac{5}{6}\)
\(\Leftrightarrow\frac{x}{13}-x=\frac{5}{6}-9\)
\(\Leftrightarrow x\left(\frac{1}{13}-1\right)=\frac{5}{6}-\frac{54}{6}\)
\(\Leftrightarrow\frac{-12}{13}x=\frac{-50}{6}\)
\(\Leftrightarrow x=\frac{-50}{6}\div\frac{-12}{13}\)
\(\Leftrightarrow x=\frac{50}{6}\times\frac{13}{12}\)
\(\Leftrightarrow x=\frac{650}{72}=\frac{325}{36}\)
\(9+\frac{x}{13}-x=\frac{5}{6}\)
\(\Rightarrow9+\frac{x}{13}-\frac{13x}{13}=\frac{5}{6}\)
\(\Rightarrow9+\frac{x-13x}{13}=\frac{5}{6}\)
\(\Rightarrow\frac{x-13x}{13}=\frac{5}{6}-9\)
\(\Rightarrow\frac{x-13x}{13}=-\frac{49}{6}\)
\(\Rightarrow x-13x=-\frac{49}{6}\cdot13=-\frac{637}{6}\)
\(\Rightarrow-12x=-\frac{637}{6}\)
\(\Rightarrow x=-\frac{637}{6}:(-12)=\frac{637}{72}\)
a)=(3/8+10/16)+(7/12+10/24)
=1+1=2
c)=(4/6+14/6)+(7/13+19/13)+(17/9+1/9)
=3+2+2=7
\(\frac{9+x}{13-x}=\frac{5}{6}\)
\(\Leftrightarrow6\left(9+x\right)=5\left(13-x\right)\)
\(\Leftrightarrow54+6x=65-5x\)
\(\Leftrightarrow54-65=-5x-6x\)
\(\Leftrightarrow-11=-11x\)
\(\Leftrightarrow x=\frac{11}{11}\)
\(\Leftrightarrow x=1\)
\(\frac{9+x}{13-x}=\frac{5}{6}\)
\(\Rightarrow\text{ }6\left(9+x\right)=5\left(13-x\right)\)
\(\Rightarrow\text{ }54+6x=65-5x\)
\(\Rightarrow\text{ }54-65=-5x-6x\)
\(\Rightarrow\text{ }-11=-11x\)
\(\Rightarrow\text{ }x=-11\text{ : }\left(-11\right)\)
\(\Rightarrow\text{ }x=1\)
1.
7/15:(1/2-9/10xX)-1/6=13/6
=>7/15:(1/2-9/10xX)=13/6+1/6
=>7/16:(1/2-9/10xX)=7/3
=>1/2-9/10xX=7/16:7/3
=>1/2-9/10xX=3/16
=>9/10xX=1/2-3/16
=>9/10xX=5/16
=>X=5/16:9/10
=>X=25/72
a, \(\dfrac{7}{8}\) \(\times\) \(\dfrac{3}{13}\) + \(\dfrac{4}{9}\) \(\times\) \(\dfrac{4}{13}\)
= \(\dfrac{1}{13}\) \(\times\)( \(\dfrac{21}{8}\) + \(\dfrac{16}{9}\))
= \(\dfrac{1}{13}\) \(\times\)( \(\dfrac{189}{72}\) + \(\dfrac{128}{72}\))
= \(\dfrac{1}{13}\) \(\times\) \(\dfrac{317}{73}\)
= \(\dfrac{317}{949}\)
b, \(\dfrac{6}{5}\) + \(\dfrac{7}{3}\) + \(\dfrac{8}{9}\)
= \(\dfrac{54}{45}\) + \(\dfrac{105}{45}\) + \(\dfrac{40}{45}\)
= \(\dfrac{199}{45}\)
c, 23 : \(\dfrac{5}{14}\) + \(\dfrac{6}{7}\) + \(\dfrac{4}{9}\)
= \(\dfrac{322}{5}\) + \(\dfrac{6}{7}\) + \(\dfrac{4}{9}\)
= \(\dfrac{20286}{315}\) + \(\dfrac{270}{315}\) + \(\dfrac{140}{315}\)
= \(\dfrac{20696}{315}\)
d, 4\(\dfrac{1}{4}\) + 7\(\dfrac{3}{7}\) - 2\(\dfrac{4}{17}\)
= 4 + \(\dfrac{1}{4}\) + 7 + \(\dfrac{3}{7}\) - 2 - \(\dfrac{4}{17}\)
= (4+7-2) + (\(\dfrac{1}{4}\) + \(\dfrac{3}{7}\) - \(\dfrac{4}{17}\))
= 9 + \(\dfrac{119}{476}\) + \(\dfrac{204}{476}\) - \(\dfrac{112}{476}\)
= 9\(\dfrac{211}{476}\) = \(\dfrac{4495}{476}\)
e, 8 - (9\(\dfrac{2}{11}\) + \(\dfrac{8}{33}\))
= 8 - 9 - \(\dfrac{2}{11}\) - \(\dfrac{8}{33}\)
= -1 - \(\dfrac{2}{11}\) - \(\dfrac{8}{33}\)
= \(\dfrac{-33}{33}\) - \(\dfrac{-6}{33}\) - \(\dfrac{8}{33}\)
= - \(\dfrac{47}{33}\)
\(\dfrac{9+x}{13-x}\) = \(\dfrac{5}{6}\)
(9+x)*6=(13-x)*5
54+x6 = 65-x5
54=65-x5-x6
54= 65-11x
65-54=11x
11=11x
x=1