a) x - \((\dfrac{5}{4}-\dfrac{7}{5})\) = \(\dfrac{9}{20}\) b) 9 - x = \(\dfrac{8}{7}\) - \((-\dfrac{7}{8})\)
c) -1,2 + (-0,8) + 0,25 + 5,75 - 2021
d) -0,1 + \(\dfrac{16}{9}\) + 11,1 + \(\dfrac{-20}{9}\)
e) \(\dfrac{17}{11}-(\dfrac{6}{5}-\dfrac{16}{11})+\dfrac{26}{5}\) f)\(\dfrac{39}{5}+(\dfrac{9}{4}-\dfrac{9}{5})-(\dfrac{5}{4}+\dfrac{6}{7})\)
a: =>x-(-3/20)=9/20
=>x=9/20-3/20=6/20=3/10
b: =>9-x=8/7+7/8=64/56+49/56=113/56
=>x=391/56
d: \(=\dfrac{-1}{10}+\dfrac{16}{9}+\dfrac{111}{10}+\dfrac{-20}{9}\)
\(=\dfrac{110}{10}-\dfrac{4}{9}\)
=11-4/9=95/9
a/
\(\Rightarrow x-\left(-\dfrac{3}{20}\right)=\dfrac{9}{20}\\ x+\dfrac{3}{20}=\dfrac{9}{20}\\ x=\dfrac{9}{20}-\dfrac{3}{20}\\ x=\dfrac{6}{20}\\ =\dfrac{3}{10}\)
b/
\(\Rightarrow9-x=\dfrac{8}{7}+\dfrac{7}{8}\\ 9-x=\dfrac{113}{56}\\ x=9-\dfrac{113}{56}\\ x=\dfrac{391}{56}\)
c/
\(=\left(-1,2+-0,8\right)+\left(0,25+5,75\right)-2021\\ =-2+6-2021=-2017\)
d/
\(=-\dfrac{1}{10}+\dfrac{16}{9}+\dfrac{111}{10}+\dfrac{-20}{9}\\ =\left(-\dfrac{1}{10}+\dfrac{111}{10}\right)+\left(\dfrac{16}{9}+\dfrac{-20}{9}\right)\\ =\dfrac{110}{10}+-\dfrac{4}{9}\\=11-\dfrac{4}{9}\\ =\dfrac{95}{9}\)
e/
\(=\dfrac{17}{11}-\dfrac{6}{5}+\dfrac{16}{11}+\dfrac{26}{5}=\left(\dfrac{17}{11}+\dfrac{16}{11}\right)+\left(\dfrac{-6}{5}+\dfrac{26}{5}\right)\\ =\dfrac{33}{11}+\dfrac{20}{5}=3+4=7\)
f/
\(=\dfrac{39}{5}+\dfrac{9}{4}-\dfrac{9}{5}-\dfrac{5}{4}-\dfrac{6}{7}=\left(\dfrac{39}{5}-\dfrac{9}{5}\right)+\left(\dfrac{9}{4}-\dfrac{5}{4}\right)-\dfrac{6}{7}\\ =\dfrac{30}{5}+\dfrac{4}{4}-\dfrac{6}{7}=6+1-\dfrac{6}{7}\\ =7-\dfrac{6}{7}=\dfrac{43}{7}\)
