Bài 1:

    \(\left(-0,125\right)\times7,9\times80\)

\(=\left(-0,9875\right)\times80\)

\(=79.\)

    \(\left(0,125\right)\times1\times0,25\times8\times\left(-4\right)\)

\(=0,125\times0,25\times8\times\left(-4\right)\)

\(=0,03125\times8\times\left(-4\right)\)

\(=0,25\times\left(-4\right)\)

\(=\left(-1\right).\)

Bài 2:

\(x+\frac{8}{3}^2=\frac{1}{9}\)

\(x+16=\frac{1}{9}\)

           \(x=\frac{1}{9}-16.MSC=9\)

           \(x=\frac{1}{9}-\frac{144}{9}\)

           \(x=\frac{-143}{9}.\)

9/8 + 3/8x = 0,125 = 1/8

3/8x = 1/8 - 9/8 = -1

=> x = -1 : 3/8 = -8/3        

chỉ có một lần cân bằng cân Rôbecvan và 1 quả cân 1kg làm thế nào ta có thể lấy 2kg gạo ra khỏi bao gạo chứa 5kg

8 x 1,1 x 3 x 0,125

= 0,125 x 8 x 3 x 1,1

= 1 x 3 x 1,1

= 3  x 1,1

= 3,3

\(8\times1,1\times3\times0,125\\ =\left(8\times0,125\right)\times\left(1,1\times3\right)\\ =1\times3,3\\ =3,3\)

\(\dfrac{1}{12345}-3\dfrac{3}{4}+0,125+3\dfrac{3}{4}-\dfrac{1}{8}-\dfrac{1}{12345}\)

\(=\left(\dfrac{1}{12345}-\dfrac{1}{12345}\right)+\left(-3\dfrac{3}{4}+3\dfrac{3}{4}\right)+\left(0,125-\dfrac{1}{8}\right)\)

\(=0+0+\left(\dfrac{1}{8}-\dfrac{1}{8}\right)\)

\(=0\)

#Toru

cảm ơn bn nhiều nhé

hình như đề sai

a)

\(\begin{array}{l}\frac{{ - 3}}{{10}} - 0,125 + \frac{{ - 7}}{{10}} + 1,125 \\= \left( {\frac{{ - 3}}{{10}} + \frac{{ - 7}}{{10}}} \right) + \left( {1,125 - 0,125} \right)\\ =  - 1 + 1 \\= 0\end{array}\)       

b)

\(\begin{array}{l}\frac{{ - 8}}{3}.\frac{2}{{11}} - \frac{8}{3}:\frac{{11}}{9} \\= \frac{8}{3}.\frac{{ - 2}}{{11}} - \frac{8}{3}.\frac{9}{{11}}\\ = \frac{8}{3}.\left( {\frac{{ - 2}}{{11}} - \frac{9}{{11}}} \right)\\ =\frac{{ - 8}}{3}.\frac{-11}{11}\\= \frac{8}{3}.\left( { - 1} \right) \\= \frac{{ - 8}}{3}\end{array}\)

a, \(\dfrac{3}{5}.\left(-\dfrac{8}{3}\right)-\dfrac{3}{5}:\left(-\dfrac{3}{2}\right)=\dfrac{3}{5}.\left(-\dfrac{8}{3}\right)-\dfrac{3}{5}.\left(-\dfrac{2}{3}\right)==\dfrac{3}{5}\left(-\dfrac{8}{3}-\dfrac{2}{3}\right)=\dfrac{3}{5}.\left(-\dfrac{10}{3}\right)=-2\)

b, \(-\dfrac{5}{6}.\left(-\dfrac{12}{7}\right)-\left(-\dfrac{21}{15}\right)=-\dfrac{5}{6}.\left(-\dfrac{12}{7}\right)+\dfrac{7}{5}=\dfrac{10}{7}+\dfrac{7}{5}=\dfrac{50+49}{35}=\dfrac{99}{35}\)

a: \(=\dfrac{3}{5}\cdot\left(-\dfrac{8}{3}+\dfrac{-2}{3}\right)=\dfrac{3}{5}\cdot\dfrac{-10}{3}=-2\)

c: \(=\left(0.125\right)^{650}\cdot8^{102}\)

\(=\left(0.125\cdot8\right)^{102}\cdot\left(0.125\right)^{548}\)

\(=\dfrac{1}{8^{548}}\)

a) 0,125³.8³

=(0,125.8)³

=1³

=1.

b)(-39)⁴:13⁴

=39⁴:13⁴

=(39:13)⁴

=3⁴

=81

a)0,125³ . 8³ = (0,125 . 8)³ = 1³ = 1

b) (-39)⁴ : 13⁴ =  ((-39 ): 13 )⁴ = 3⁴ = 81