Phiền bạn ghi rõ đề

a) 17 + 15 + (-27)

= (17 - 27) + 15

= -10 + 15

= 5

b) 13.75 + 25.13 - 300

= 13.(75 + 26) - 300

= 13.100 - 300

= 1300 - 300

= 1000

c) 80 - (4.5² - 5.2³) + 2021⁰

= 80 - (4.25 - 5.8) + 1

= 80 - (100 - 40) + 1

= 80 - 60 + 1

= 20 + 1

= 21

a) \(-\dfrac{215}{340}=-\dfrac{43}{68}\)

b) \(\dfrac{25\cdot13}{26\cdot35}=\dfrac{5}{2\cdot7}=\dfrac{5}{14}\)

c) \(\dfrac{-2017\cdot2016+1}{-2015\cdot\left(-2017\right)+2016}=-1\)

\(a,\dfrac{-215}{340}=\dfrac{-215:5}{340:5}=\dfrac{-43}{68}\)

\(b,\dfrac{25.13}{26.35}=\dfrac{5.5.13}{2.13.7.5}=\dfrac{5}{2.7}=\dfrac{5}{14}\)

\(\dfrac{-2017.2016+1}{-2015.-2017+2016}=-1\)

c: \(23\cdot75+25\cdot10+25\cdot13+180\)

\(=25\left(23\cdot3+10+13\right)+180\)

\(=25\cdot98+180\)

=2450+180

=2630

giúp mik đi nhé 

mik đang cần gấp nèeee

a,-7/12

b,5/14

c,-3/8

d,-1

,

,,,,,,,,,ư

\(23\cdot75+25\cdot10+25\cdot13+180\\ =23\cdot75+25\cdot\left(10+13\right)+180\\ =23\cdot75+25\cdot23+180\\ =23\cdot\left(75+25\right)+180\\ =23\cdot100+180\\ =2300+180\\ =2480\)

a, \(-\dfrac{315}{540}\) = \(\dfrac{-315:45}{540:45}\) = \(\dfrac{-7}{12}\)        b,   \(\dfrac{25.13}{26.35}\) = \(\dfrac{25.13:5:13}{26.35:13:5}\) = \(\dfrac{5}{14}\)

c,     \(\dfrac{6.9-2.17}{63.3-119}\) = \(\dfrac{2.3.9-2.17}{7.9.3-7.17}\) = \(\dfrac{2.(27-17)}{7.(7-17)}\) = \(\dfrac{2}{7}\)

d, \(\dfrac{3.13-13.18}{15.40-80}\) = \(\dfrac{3.13(1-6)}{40.(15-2)}\) = \(\dfrac{-3.13.5}{40.13}\) = \(\dfrac{-15}{40}\) = \(\dfrac{-15:5}{40:5}\) = \(-\dfrac{3}{8}\)