Question

giúp mình bài 1 với

Answer 1

bài thi à

Answer 2

Bài 1: 

a: \(=\dfrac{-7}{25}-\dfrac{8}{25}=\dfrac{-15}{25}=-\dfrac{3}{5}\)

b: \(=\dfrac{-3}{4}-\dfrac{5}{7}=\dfrac{-21-20}{28}=-\dfrac{41}{28}\)

c: \(=\dfrac{-3}{17}+\dfrac{2}{3}+\dfrac{3}{17}=\dfrac{2}{3}\)

d: \(D=\dfrac{-3}{31}-\dfrac{28}{31}+\dfrac{-6}{17}+\dfrac{-11}{17}+\dfrac{1}{25}-\dfrac{5}{25}=-2-\dfrac{4}{25}=\dfrac{-54}{25}\)

Answer 3

a)\(\dfrac{7}{-25}+\dfrac{-8}{25}=\dfrac{-7}{25}+\dfrac{-8}{25}=\dfrac{-15}{25}=\dfrac{-3}{5}\)

b)\(\dfrac{-18}{24}-\dfrac{15}{21}=\dfrac{-126}{168}-\dfrac{120}{168}=\dfrac{-246}{168}=\dfrac{-41}{28}\)

c)\(\dfrac{-3}{17}+\left(\dfrac{2}{3}+\dfrac{3}{17}\right)=\dfrac{-3}{17}+\dfrac{2}{3}+\dfrac{3}{17}=\left(\dfrac{-3}{17}+\dfrac{3}{17}\right)+\dfrac{2}{3}=0+\dfrac{2}{3}=\dfrac{2}{3}\)