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-3 + 7 -9-54 + 3 +50 +13
= (-3+3)+ (13 -9)+ 7 + 54 - 50
= 0 + 4 + 7 + 54 - 50
=0 + 7 + 54 - ( 50 +4 )
= 0 + 7 + 54 - 54
= 7 + 0
=7
cho mình chữa lại đề nha: cái phân số cuối 7/13 chữa lại thành 7/23.
\(-\dfrac{5}{7}\times\dfrac{2}{13}+\dfrac{-5}{7}\times\dfrac{3}{13}-\dfrac{5}{7}\times\dfrac{8}{13}\)
\(=-\dfrac{5}{7}\left(\dfrac{2}{13}+\dfrac{3}{13}+\dfrac{8}{13}\right)\)
\(=-\dfrac{5}{7}\times\dfrac{13}{13}\)
\(=-\dfrac{5}{7}\times1=-\dfrac{5}{7}\)
1+(-5)+9+(-13)+...+(-197)+201
=-4+(-4)+...+(-4)
Có:
(201-1):8+1=26(cặp)
=>Tổng trên là:
26x(-4)=-104
tick nha
\(\dfrac{5}{13}.-\dfrac{3}{10}.-\dfrac{13}{5}\)
\(=\dfrac{5.3.13}{13.10.5}\)
\(=\dfrac{3}{10}\)
\(\dfrac{-5}{10}+\dfrac{12}{28}-\dfrac{3}{27}-\dfrac{7}{18}+\dfrac{20}{35}\\ =\left(\dfrac{-1}{2}-\dfrac{1}{9}-\dfrac{7}{18}\right)+\left(\dfrac{3}{7}+\dfrac{4}{7}\right)\\ =\left(\dfrac{-9}{18}-\dfrac{2}{18}-\dfrac{7}{18}\right)+\dfrac{7}{7}\\ =\dfrac{-18}{18}+1\\ =\left(-1\right)+1\\ =0\)
a: =-5/9-4/9+8/15+7/15-2/11=-2/11
b: =10/17+7/17-5/13-8/13+11/25
=11/25
c: =(9/12-2/12)*3/2=7/12*3/2=21/24=7/8
d: =(31/10-25/10)*3-2
=3/5*3-2
=9/5-2
=-1/5
\(\dfrac{-5}{7}\cdot\dfrac{3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+1\dfrac{5}{7}=\dfrac{5}{7}\cdot\dfrac{-3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+\dfrac{12}{7}\cdot1=\dfrac{5}{7}\cdot\left(\dfrac{-3}{13}-\dfrac{10}{13}\right)+\dfrac{12}{7}=\dfrac{5}{7}-1+\dfrac{12}{7}=-\dfrac{5}{7}+\dfrac{12}{7}=\dfrac{7}{7}=1\)
=-5/7(3/13+10/13)+12/7
=-5/7+12/7=1