Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a: \(=\dfrac{-12}{7}\left(\dfrac{4}{35}+\dfrac{31}{35}\right)-\dfrac{2}{7}=\dfrac{-12}{7}-\dfrac{2}{7}=-2\)
b: =(-4)+(-4)+...+(-4)
=-4*25=-100
c: \(=157\cdot\left(-37\right)-41\cdot53+37\cdot157+51\cdot53\)
=10*53
=530
1: =5/13+8/13-20/41-21/41-5/17
=1-1-5/17=-5/17
2: =1/5+4/5-2/9-7/9+16/17
=16/17+1-1=16/17
3: =1/3-1/5+1/5-1/7+...+1/99-1/101
=1/3-1/101
=98/303
5.\(-\dfrac{3}{7}+\dfrac{5}{13}+\dfrac{-4}{12}=-\dfrac{103}{273}\)
b.\(-\dfrac{5}{21}+\dfrac{-2}{21}+\dfrac{8}{24}=\dfrac{-5-2}{21}+\dfrac{8}{24}=-\dfrac{7}{21}+\dfrac{8}{24}=-\dfrac{1}{3}+\dfrac{8}{24}=0\)
c.\(\dfrac{5}{13}+\dfrac{-5}{7}+\dfrac{-20}{41}+\dfrac{8}{13}+\dfrac{-21}{41}=\left(\dfrac{5}{13}+\dfrac{8}{13}\right)+\left(\dfrac{-20}{41}+\dfrac{-21}{41}\right)+-\dfrac{5}{7}=1-1-\dfrac{5}{7}=-\dfrac{5}{7}\)
Ta có: \(A=\dfrac{5}{13}+\dfrac{-5}{7}+\dfrac{-20}{41}+\dfrac{8}{13}+\dfrac{-21}{41}\)
\(=\left(\dfrac{5}{13}+\dfrac{8}{13}\right)+\left(\dfrac{-20}{41}+\dfrac{-21}{41}\right)+\dfrac{-5}{7}\)
\(=1-1+\dfrac{-5}{7}\)
\(=\dfrac{-5}{7}\)
\(M=\dfrac{120-\dfrac{1}{2}.40.5.\dfrac{1}{5}.20.\dfrac{1}{4}-20}{1+5+....+41}\\ =\dfrac{120-20.5-20}{1+5+...+41}\\ =\dfrac{0}{1+5+...+41}\\ =0\)
\(N=10101\left(\dfrac{6}{3.7.11.13.37}+\dfrac{6}{2.3.7.11.13.37}-\dfrac{7}{3.7.11.13.37}\right)\\ =10101\left(-\dfrac{2}{2.3.7.11.13.37}+\dfrac{6}{2.3.7.11.13.37}\right)\\ =3.7.13.37\left(\dfrac{4}{2.3.7.11.13.37}\right)=\dfrac{4}{2.11}=\dfrac{2}{11}\)
\(-\dfrac{5}{7}\left(\dfrac{-19}{41}+-\dfrac{21}{41}+1\right)=-\dfrac{5}{7}.\dfrac{1}{41}=-\dfrac{5}{287}\)
\(=\dfrac{-5}{7}\left(\dfrac{19}{41}+\dfrac{21}{41}-1\right)=\dfrac{-5}{7}\cdot\dfrac{-1}{41}=\dfrac{5}{287}\)
`8/7+419-1/7`
`=7/7+419`
`=1+419=420`
`-4/41+(-37/41+2)`
`=-(4/41+37/41)+2`
`=-1+2`
`=1`
\(\dfrac{8}{7}+419+\dfrac{-1}{7}\)
=\(\left(\dfrac{8}{7}+\dfrac{-1}{7}\right)+419\)
=1+419
=420
\(\dfrac{-4}{41}+\left(\dfrac{-37}{41}+2\right)\)
=\(\dfrac{-4}{41}+\dfrac{-37}{41}+2\)
=\(\left(\dfrac{-4}{41}+\dfrac{-37}{41}\right)+2\)
=-1+2
=1