1: =-2/9(15/17+2/17)=-2/9

2: \(=\dfrac{-6}{3}+\dfrac{-21}{90}\)

=-2-7/30=-67/30

3: \(=\dfrac{3}{4}\cdot\dfrac{7}{5}+\dfrac{9}{7}\cdot\dfrac{3}{2}\)

=21/20+27/14=417/140

4: =-25/13(5/19+14/19)=-25/13

5: =-7/5-45/21=-7/5-15/7=-124/35

1: =-2/9(15/17+2/17)=-2/9

2: =34⋅75+97⋅32=34⋅75+97⋅32

=21/20+27/14=417/140

4: =-25/13(5/19+14/19)=-25/13

5: =-7/5-45/21=-7/5-15/7=-124/35

`1, -2/9 xx 15/17 + (-2/9) xx 2/17`

`= -2/9 xx (15/17 + 2/17)`

`= -2/9 xx 17/17`

`=-2/9xx1`

`=-2/9`

__

`-5/3 xx 6/5 + (-7/9) xx 3/10`

`= -30/15 + (-21/90)`

`= -2 + (-7/30)`

`=-60/30 +(-7/30)`

`=-67/30`

__

`15/20 xx 7/5 + (-9/7) xx (-6/4)`

`=3/4 xx7/5 + (-9/7) xx(-6/4)`

`= 21/20 + 54/28`

`= 21/20 + 27/14`

`=417/140`

__

`-25/13 xx 5/19 + (-25/13) xx 14/19`

`=-25/13 xx (5/19 +14/19)`

`=-25/13 xx 19/19`

`= -25/13 xx 1`

`=-25/13`

__

`-7/13 xx 13/5 + (-9/7) xx 5/3`

`=-7/5 +(-15/7)`

`=-124/35`

1

a)103/35

b)-3/13

a: \(=\dfrac{4}{5}+\dfrac{6}{5}\cdot\dfrac{15}{7}-\dfrac{3}{7}=\dfrac{4}{5}+\dfrac{90}{35}-\dfrac{3}{7}\)

\(=\dfrac{28}{35}+\dfrac{90}{35}-\dfrac{15}{35}=\dfrac{103}{35}\)

b: \(=\dfrac{9}{13}\left(\dfrac{5}{13}-\dfrac{6}{13}-\dfrac{20}{13}\right)=\dfrac{9}{13}\cdot\dfrac{-21}{13}=\dfrac{-189}{169}\)

\(a,\frac{5}{7}+\frac{7}{13}+\frac{19}{13}+\frac{6}{5}+\frac{9}{7}+\frac{9}{5}.\)

\(=\left(\frac{5}{7}+\frac{9}{7}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)+\left(\frac{6}{5}+\frac{9}{5}\right)\)

\(=\frac{14}{7}+\frac{26}{13}+\frac{15}{5}=2+2+3=7\)

\(b,\frac{1}{10}+\frac{20}{100}+\frac{300}{1000}+\frac{4000}{10000}\)

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

a: \(=-\dfrac{5}{12}\cdot\dfrac{9}{20}\cdot\dfrac{7}{17}=-\dfrac{21}{272}\)

b: \(=\dfrac{13}{17}\left(-\dfrac{4}{5}-\dfrac{3}{4}\right)=\dfrac{-13}{17}\cdot\dfrac{31}{20}=-\dfrac{403}{340}\)

c: \(=\dfrac{-5}{7}\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{5}{7}=-\dfrac{5}{7}+\dfrac{5}{7}=0\)

d: \(=\dfrac{12}{5}-\dfrac{3}{10}=\dfrac{21}{10}\)