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Tính giá trị của biểu thức sau ( hợp lí nếu có thể ):
a) \(\left(-25\right)\times\left(-5\right)\times\left(-0,4\right)\times\left(-0,2\right)\)
\(=\left[25\times\left(-0,2\right)\right]\times\left[5\times\left(-0,4\right)\right]\)
\(=\left(-5\right)\times2\)
\(=-10\)
b) \(\left(-0,25\right)\times0,02\times40\times\left(-50\right)\times\left(-201,43\right)\)
\(=\left(-0,25\times40\right)\times\left(-50\times0,02\right)\times\left(-201,43\right)\)
\(=\left(-10\right)\times\left(-1\right)\times\left(-201,43\right)\)
\(=10\times\left(-201,43\right)\)
\(=-2014,3\)
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a) 25. ( - 5 ) . ( - 0,4 ) . ( - 0,2 ) = 25 . ( - 0,4 ) . (-5).(-0,2) = 10 . 1 =10
b) (- 0,5 ) . 5 . ( - 50 ) . 0,02 . ( - 0,2 ) . 2 = [(- 0,5 ) . 2].[( - 50 ) . 0,02]. ( - 0,2 ) = -1 . (-1) . (-0,2) = -0,2
a/
\(25.\left(-5\right).\left(-0,4\right).\left(-0,02\right)=25.-5.-0,4.-0,02=\left(25.-5\right).\left(-0,4.-0,02\right)=-125.\frac{1}{125}=-1\)
b/ \(\left(-0,5\right).5.\left(-50\right).0,02.\left(-0,2\right).2=-0,5.5.-50.0,02.-0,2.2=\left(-0,5.5\right).\left(-50.0,02\right).\left(-0,2.2\right)=-2,5.-1.-0,4=-1\)
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\(=\left(\dfrac{3}{4}-\dfrac{1}{5}\right)\cdot\left(\dfrac{2}{5}-\dfrac{4}{5}\right)\)
\(=\dfrac{11}{20}\cdot\dfrac{-2}{5}=\dfrac{-22}{100}=-\dfrac{11}{50}\)
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a) Ta được: x . 1,25 = 5. (-2) nên \(x = \frac{{5.( - 2)}}{{1,25}} = - 8\)
Vậy x = -8
b) Vì 18 : x = 2,4 : 3,6 nên \(\frac{{18}}{x} = \frac{{2,4}}{{3,6}} \Rightarrow 18.3,6 = x.2,4 \Leftrightarrow x = \frac{{18.3,6}}{{2,4}} = 27\)
Vậy x = 27
c) Vì (x+1) : 0,4 = 0,5 : 0,2 nên \(\frac{{x + 1}}{{0,4}} = \frac{{0,5}}{{0,2}} \Rightarrow (x + 1).0,2 = 0,4.0,5 \Leftrightarrow x + 1 = \frac{{0,4.0,5}}{{0,2}} = 1 \Leftrightarrow x = 0\)
Vậy x = 0
a, x= (-2). 5 :1,25 = -8
b, x= 18 : (2,4:3,6)= 18: 2/3 = 18 x 3/2 = 27
c, x+1= (0,5:0,2) x 0,4= 2,5 x 0,4= 1
=> x=1-1=0
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a) Ta có: \(\left(-2.5\cdot0.38\cdot0.4\right)-\left[0.125\cdot3.15\cdot\left(-8\right)\right]\)
\(=\left(-1\cdot0.38\right)-\left[-1\cdot3.15\right]\)
\(=-0.38+3.15\)
\(=\dfrac{277}{100}\)
b) Ta có: \(\left[\left(-20.83\right)\cdot0.2+\left(-9.17\right)\cdot0.2\right]:\left[2.47\cdot0.5-\left(-3.53\right)\cdot0.51\right]\)
\(=\dfrac{0.2\left(-20.83-9.17\right)}{3.0353}\)
\(=\dfrac{0.2\cdot\left(-30\right)}{3.0353}=\dfrac{-60000}{30353}\)
\(=\left[25\cdot\left(-0,4\right)\right]\left[\left(-5\right)\left(-0,2\right)\right]\\ =-10\cdot1=-10\)