Bài 2:
\(a.A=\dfrac{15}{43}-\left(\dfrac{21}{33}-\dfrac{28}{43}\right)-\left(\dfrac{-21}{33}\right)\\ =\dfrac{15}{43}-\dfrac{21}{33}+\dfrac{28}{43}+\dfrac{21}{33}\\ =\left(\dfrac{15}{43}+\dfrac{28}{43}\right)+\left(\dfrac{-21}{33}+\dfrac{21}{33}\right)\\ =\dfrac{43}{43}+0\\ =1\\ b.B=-5,7+\left(-19,7\right)\cdot\dfrac{19}{13}-19,3\cdot\dfrac{19}{13}\\ =-5,7+\dfrac{19}{13}\cdot\left(-19,7-19,3\right)\\ =-5,7+\dfrac{19}{13}\cdot\left(-39\right)\\ =-5,7-57\\ =-62,7\\ c.C=\left[\left(0,4\right)^{13}\cdot\left(\dfrac{2}{5}\right)^5+\left(0,16\right)^8\right]:\left[\left(0,4\right)^4\right]^4\\ =\left[\left(0,4\right)^{13}\cdot\left(0,4\right)^5+\left[\left(0,4\right)^2\right]^8\right]:\left(0,4\right)^{4\cdot4}\\ =\left[\left(0,4\right)^{18}+\left(0,4\right)^{16}\right]:\left(0,4\right)^{16}\\ =\left(0,4\right)^2+1\\ =\dfrac{4}{25}+1\\ =\dfrac{29}{25}\)
Bài 3:
\(a.\left(-0,1\right)-2x-\dfrac{1}{6}=-\dfrac{5}{6}\\ =>-\dfrac{1}{10}-2x=\dfrac{-5}{6}+\dfrac{1}{6}\\ =>-\dfrac{1}{10}-2x=\dfrac{-4}{6}=-\dfrac{2}{3}\\ =>2x=-\dfrac{1}{10}+\dfrac{2}{3}=\dfrac{17}{30}\\ =>x=\dfrac{17}{30}:2=\dfrac{17}{60}\\ b.45:\left(2x-\dfrac{1}{2}\right)^2-1=2^2\\ =>45:\left(2x-\dfrac{1}{2}\right)^2=2^2+1=5\\ =>\left(2x-\dfrac{1}{2}\right)^2=45:5\\ =>\left(2x-\dfrac{1}{2}\right)^2=9=3^2\\ TH1:3x-\dfrac{1}{2}=3\\ =>3x=3+\dfrac{1}{2}=\dfrac{7}{2}\\ =>x=\dfrac{7}{2}:3=\dfrac{7}{6}\\ TH2:3x-\dfrac{1}{2}=-3\\ =>3x=-3+\dfrac{1}{2}=-\dfrac{5}{2}\\ =>x=-\dfrac{5}{2}:3=-\dfrac{5}{6}\)
\(c.2\left(x-1\right)=5\left(3-x\right)+\left(-2024\right)^0\\ =>2x-2-5\left(3-x\right)=1\\ =>2x-2-15+5x=1\\ =>7x-17=1\\ =>7x=1+17\\ =>7x=18\\ =>x=\dfrac{18}{7}\)
a) A=\(\dfrac{15}{43}-\left(\dfrac{21}{33}-\dfrac{28}{43}\right)-\left(-\dfrac{21}{33}\right)\)
A= \(\dfrac{15}{43}-\dfrac{21}{33}+\dfrac{28}{43}+\dfrac{21}{33}\)
\(A=\left(\dfrac{15}{43}+\dfrac{28}{43}\right)+\left(\dfrac{21}{33}-\dfrac{21}{33}\right)\)
A = \(1+0=1\)
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