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\(1)\frac{12}{7}\times \frac{7}{4}+\frac{35}{11}:\frac{245}{121}\)
\(=3+\frac{35}{11}\times \frac{121}{245}\)
\(=3+\frac{11}{7}\)
\(= 3\frac{1}{7}(=\frac{22}{7})\)
\(\frac{6-2}{5}+\frac{3}{5.3}\)
\(=\frac{4}{5}+\frac{1}{5.1}\)
\(=\frac{4}{5}+\frac{1}{5}\)
\(=\frac{5}{5}=1\)
a. 6 x 3 - ( \(\frac{2}{5}+\frac{3}{5}\)) = 6 x 3 - \(\frac{5}{5}\)= 6 x 3 - 1 = 18 - 1 = 17
b.( \(\frac{31}{35}-\frac{4}{7}\)) x \(\frac{8}{7}\): 2 =\(\frac{11}{35}\)x \(\frac{8}{7}\): 2 =\(\frac{88}{245}\): 2 = \(\frac{88}{490}\)= \(\frac{44}{245}\)= ...........rút gọn đến khi hết
a) \(6-\frac{2}{5}+\frac{3}{5}\times3\)
\(=6-\frac{2}{5}+\frac{9}{5}\)
\(=\frac{30}{5}-\frac{2}{5}+\frac{9}{5}\)
\(=\frac{28}{5}+\frac{9}{5}\)
\(=\frac{37}{5}\)
b) \(\left(\frac{31}{35}-\frac{4}{7}\right)\times\frac{8}{7}:2\)
\(=\frac{11}{35}\times\frac{8}{7}:2\)
\(=\frac{88}{245}:2\)
\(=\frac{44}{245}\)
\(a,\left(\dfrac{31}{35}-\dfrac{4}{7}\right)\times\dfrac{8}{7}:2\\ =\left(\dfrac{31}{35}-\dfrac{4\times5}{35}\right)\times\dfrac{8}{7}:2\\ =\dfrac{11}{35}\times\dfrac{8}{7}:2\\ =\dfrac{88}{245}:2\\ =\dfrac{44}{245}\\ b,\left(1-\dfrac{1}{2}\right)\times\left(1-\dfrac{1}{3}\right)\times\left(1-\dfrac{1}{4}\right)\times\left(1-\dfrac{1}{5}\right)\\ =\left(\dfrac{2-1}{2}\right)\times\left(\dfrac{3-1}{3}\right)\times\left(\dfrac{4-1}{4}\right)\times\left(\dfrac{5-1}{5}\right)\\ =\dfrac{1}{2}\times\dfrac{2}{3}\times\dfrac{3}{4}\times\dfrac{4}{5}\\ =\dfrac{1}{3}\times\dfrac{3}{4}\times\dfrac{4}{5}\\ =\dfrac{1}{4}\times\dfrac{4}{5}=\dfrac{1}{5}\)
a, ( \(\dfrac{31}{35}\) - \(\dfrac{4}{7}\)) \(\times\) \(\dfrac{8}{7}\): 2
= \(\left(\dfrac{31}{35}-\dfrac{20}{35}\right)\) \(\times\) \(\dfrac{8}{7}\) : 2
= \(\dfrac{11}{35}\) \(\times\) \(\dfrac{8}{7}\) \(\times\) \(\dfrac{1}{2}\)
= \(\dfrac{44}{35}\) \(\times\) \(\dfrac{4}{7}\)
= \(\dfrac{44}{245}\)
b, ( 1 - \(\dfrac{1}{2}\)) \(\times\) ( 1 - \(\dfrac{1}{3}\)) \(\times\) ( 1 - \(\dfrac{1}{4}\)) \(\times\) ( 1 - \(\dfrac{1}{5}\))
= \(\dfrac{1}{2}\) \(\times\) \(\dfrac{2}{3}\) \(\times\) \(\dfrac{3}{4}\) \(\times\) \(\dfrac{4}{5}\)
= \(\dfrac{1}{5}\) \(\times\) \(\dfrac{2\times3\times4}{2\times3\times4}\)
= \(\dfrac{1}{5}\)
a) \(6-\dfrac{2}{5}+\dfrac{3}{5}\) x \(3\)
\(=6-\dfrac{2}{5}+\dfrac{9}{5}\)
\(=\dfrac{30}{5}-\dfrac{2}{5}+\dfrac{9}{5}\)
\(=\dfrac{30-2+9}{5}=\dfrac{37}{5}\)
b) \(\left(\dfrac{31}{35}-\dfrac{4}{7}\right)\) x \(\dfrac{8}{7}:2\)
\(=\left(\dfrac{31}{35}-\dfrac{20}{35}\right)\) x \(\dfrac{8}{7}:2\)
\(=\dfrac{11}{35}\) x \(\dfrac{8}{7}:2\)
\(=\dfrac{11}{35}\) x \(\dfrac{8}{7}\) x \(\dfrac{1}{2}\)
\(=\dfrac{\text{11 x 8 x 1}}{\text{ 35 x 7 x 2}}=\dfrac{88}{490}=\dfrac{88}{245}\)
a) 6−25+356−25+35 x 33
=6−25+95=6−25+95
=305−25+95=305−25+95
=30−2+95=375=30−2+95=375
b) (3135−47)(3135−47) x 87:287:2
=(3135−2035)=(3135−2035) x 87:287:2
=1135=1135 x 8
có ai biết làm bài này thì giải giúp mình với nhé
( x + 1 ) + ( x + 3 ) + ( x + 7 ) + ( x + 11 ) + .......... + ( x + 31 ) + ( x + 33 ) = 306
( x + x + x + x + ......... + x + x ) + ( 1 + 3 + 7 + 11 + .......... + 31 + 33) = 306
\(\Rightarrow\) 17x + 289 = 306
17x = 306 - 289
17x = 17
x = 17 : 17
x = 1