3/5

3/5

\(\dfrac{3}{5}\)

(\(\dfrac{9}{25}\) - 2.18) : (\(\dfrac{19}{5}\) + 0,2)

=(\(\dfrac{9}{25}\) - 2.18) : (\(\dfrac{19}{5}\) +\(\dfrac{1}{5}\) )

=(\(\dfrac{9}{25}\)- 36) : 4

=\(\dfrac{-117}{5}\) : 4

= \(\dfrac{-117}{20}\)

(\(\dfrac{9}{25}\)-2.18) : (\(\dfrac{19}{5}\) +0,2)

= (\(\dfrac{9}{25}\)- 2.18) : (\(\dfrac{19}{5}\)+\(\dfrac{1}{5}\))

= (\(\dfrac{9}{25}\)-36): 4

= \(\dfrac{-891}{25}\):4

=\(\dfrac{-891}{100}\)

=(1/5+3/5+4/5+2/5)

=10/5=2

\(=\dfrac{1}{5}+\dfrac{2}{5}+\dfrac{3}{5}+\dfrac{4}{5}=\dfrac{10}{5}=2\)

=1/5+2/5+51/85+4/5

=7/5+51/85

=119/85+51/85

=170/85=2

a)\(=12\times3+4\times12+12\times3=12\times\left(3+4+3\right)=12\times10=120\)

b)\(=25\times7-25\times2-3\times25-2\times25=25\times\left(7-2-3-2\right)=0\)

A) 12x3+4x12+36

=12x3+4x12+12x3

=12x(3+4+3)

=120

2:

a: \(=\dfrac{1}{3}\left(-\dfrac{4}{5}-\dfrac{6}{5}\right)=-\dfrac{1}{3}\cdot2=-\dfrac{2}{3}\)

1:

\(A=7-\dfrac{3}{4}+\dfrac{1}{3}-6-\dfrac{5}{4}+\dfrac{4}{3}-5+\dfrac{7}{4}-\dfrac{5}{3}\)

\(=-4-\dfrac{1}{4}=-\dfrac{17}{4}\)

Bài 1:

\(A=\left(7-\dfrac{3}{4}+\dfrac{1}{3}\right)-\left(6+\dfrac{5}{4}-\dfrac{4}{3}\right)-\left(5-\dfrac{7}{4}+\dfrac{5}{3}\right)\)

\(A=7-\dfrac{3}{4}+\dfrac{1}{3}-6-\dfrac{5}{4}+\dfrac{4}{3}-5+\dfrac{7}{4}-\dfrac{5}{3}\)

\(A=\left(7-6-5\right)-\left(\dfrac{3}{4}+\dfrac{5}{4}-\dfrac{7}{4}\right)+\left(\dfrac{1}{3}+\dfrac{4}{3}-\dfrac{5}{3}\right)\)

\(A=-4-\dfrac{3+5-7}{4}+\dfrac{1+4-5}{3}\)

\(A=-4-\dfrac{1}{4}+\dfrac{0}{3}\)

\(A=-\dfrac{16}{4}-\dfrac{1}{4}+0\)

\(A=\dfrac{-16-1}{4}\)

\(A=-\dfrac{17}{4}\)

Bài 2:

\(\dfrac{1}{3}\cdot-\dfrac{4}{5}+\dfrac{1}{3}\cdot-\dfrac{6}{5}\)

\(=\dfrac{1}{3}\cdot\left(-\dfrac{4}{5}-\dfrac{6}{5}\right)\)

\(=\dfrac{1}{3}\cdot\dfrac{-4-6}{5}\)

\(=\dfrac{1}{3}\cdot\dfrac{-10}{5}\)

\(=\dfrac{1}{3}\cdot-2\)

\(=-\dfrac{2}{3}\)

\(\frac{5}{3}+-\frac{2}{7}-\left(-\frac{1}{2}\right)=\frac{29}{21}-\left(-\frac{1}{2}\right)=\frac{79}{42}\)

b . tương tự 

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