\(-\frac{2}{3}+\frac{1}{5}.\frac{-10}{7}\\ =-\frac{2}{3}+\frac{1.-10}{5.7}\\ =-\frac{2}{3}+\frac{-2}{7}\\ =-\frac{14}{21}+\frac{-6}{21}\\ =-\frac{20}{21}\)

=\(\frac{-2}{3}+\frac{1}{5}.\frac{-10}{7}\)

=\(\frac{-2}{3}+\frac{-2}{7}\)

=\(\frac{-20}{21}\)

\(a,25.\left(7-27\right)+27.25\)

\(=25.7-27+27.25\)

\(=27.\left(25+25\right)-7\)

\(=27.50-7=135-7=128\)( ko chắc )

\(b,\left(-3\right)^2.\left(-2\right)^3\)

\(=9.\left(-8\right)=-72\)

a) 2.5³-3.2+4⁵:4³
= 2.125-6+16
= 250+10
= 260

250-6 + 4^5-3 =>250-6 + 4² =>250-6 + 16 =>260

=260

\(=\dfrac{-3}{5}:\dfrac{7}{5}-\dfrac{3}{5}:\dfrac{7}{5}+2\dfrac{3}{5}\)

\(=-\dfrac{6}{5}\times\dfrac{5}{7}+\dfrac{13}{5}=\dfrac{61}{35}\)

=\(\dfrac{-3}{5}\).\(\dfrac{5}{7}\)-\(\dfrac{3}{5}\).\(\dfrac{5}{7}\)+\(\dfrac{13}{5}\)

=(\(\dfrac{-3}{5}\)-\(\dfrac{3}{5}\)+\(\dfrac{13}{5}\)).\(\dfrac{5}{7}\)
=\(\dfrac{13}{5}\).\(\dfrac{5}{7}\)
=\(\dfrac{13}{1}\).\(\dfrac{1}{7}\)
=\(\dfrac{13}{7}\)

6/7+(5/8-3/16):5.-4

=6/7+(10/16-3/16):5.-4

=6/7+7/16:5.-4

=6/7+7/80.-4

=6/7+-28/80

=6/7+7/20

120/140+49/140

=169/140

1: 0,35*12,4=0,35*2,4+0,35*10=3,5+0,84=4,34

2: =0,1-2,34=-2,24

3: =5-2,9=2,1

4: \(=2,5\left(10,124-0,124\right)=10\cdot2,5=25\)

5: =-3/7+1/13

=-39/91+7/91

=-32/91

6: =-1/3+1/3=0

a) \(=\left(13\dfrac{2}{7}+2\dfrac{5}{7}\right):\left(-\dfrac{8}{9}\right)\)

\(=16:\dfrac{-8}{9}=\dfrac{-8\cdot\left(-2\right)\cdot9}{-8}=-18\)

b) 

\(=\left(\dfrac{-6}{11}\cdot\dfrac{11}{-6}\right)\cdot\dfrac{7\cdot10\cdot\left(-2\right)}{10}\)

\(=-14\)

c) \(=\dfrac{-1}{2}\cdot\dfrac{4}{3}\cdot\dfrac{-7}{2}\)

\(=\dfrac{-1\cdot2\cdot2\cdot\left(-7\right)}{2\cdot3\cdot2}=\dfrac{7}{3}\)