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12 tháng 11 2017

a, (-0.25) * 7.9 * 40 = [ (-0.25) * 40] * 7.9 = -10 * 7.9 = -79

b, ( 3/2 )^3 * 2^3 = ( 3/2*2) ^3 = 3^3 = 27

c, (1.75 / \(\frac{7}{2}\)) * \(\frac{4}{5}\)= ( 7/4 * 7/2 ) *4/5 = \(\frac{49}{10}\)

d, \(\frac{11}{2}\cdot4\frac{5}{3}-2\frac{5}{3}\cdot\frac{11}{2}\)\(\frac{11}{2}\cdot\left(\frac{17}{3}-\frac{11}{3}\right)\)\(\frac{11}{2}\cdot\frac{6}{3}\)\(\frac{11}{2}\cdot2\)=11

6 tháng 1 2016

A=0; B=4

27 tháng 9 2021

A=0; 

B=4Chúc bạn học tốt!

a) \(\left(0,25\right)^3\cdot32=0,015625\cdot32=0,5\)

b) \(\left(-0,125\right)^3\cdot80^4=\dfrac{-1}{512}\cdot40960000=80000\)

c) \(\dfrac{8^2\cdot4^5}{2^{20}}=\dfrac{2^{3^2}\cdot2^{2^5}}{2^{20}}=\dfrac{2^6\cdot2^{10}}{2^{20}}=\dfrac{2^{16}}{2^{20}}=\dfrac{1}{2^4}=\dfrac{1}{16}\)

d) \(\dfrac{81^{11}\cdot3^{17}}{27^{10}\cdot9^{15}}=\dfrac{3^{4^{11}}\cdot3^{17}}{3^{3^{10}}\cdot3^{2^{15}}}=\dfrac{3^{44}\cdot3^{17}}{3^{30}\cdot3^{30}}=\dfrac{3^{61}}{3^{60}}=3\)

31 tháng 10 2020

\(a,\frac{1}{3}x+0.25=\frac{5}{7}\)

\(\Leftrightarrow\frac{1}{3}x=\frac{13}{28}\)

\(\Leftrightarrow x=\frac{39}{28}\)

vậy...

\(b,\frac{11}{12}x+0,25=\frac{5}{6}\)

\(\Leftrightarrow\frac{11}{12}x=\frac{7}{12}\)

\(\Leftrightarrow x=\frac{7}{11}\)

vậy.....

\(c,\left(\frac{-1}{3}\right)^2+\frac{2}{3}x=\frac{1}{4}\)

\(\Leftrightarrow\frac{1}{9}+\frac{2}{3}x=\frac{1}{4}\)

\(\Leftrightarrow\frac{2}{3}x=\frac{5}{36}\)

\(\Leftrightarrow x=\frac{5}{24}\)

vậy......

\(d,\left(3x+2\right)^3=-\frac{8}{125}\)

\(\Leftrightarrow3x+2=-\frac{2}{5}\)

\(\Leftrightarrow3x=-\frac{12}{5}\)

\(\Leftrightarrow x=-\frac{4}{5}\)

vậy.......

31 tháng 10 2020

\(\frac{1}{3x}+0,25=\frac{5}{7}\)

\(\frac{1}{3x}+\frac{1}{4}=\frac{5}{7}\)

\(\frac{1}{3x}=\frac{13}{28}\)

\(3x=\frac{28}{13}\)

\(x=\frac{28}{39}\)

\(\frac{11}{12x}+0,25=\frac{5}{6}\)

\(\frac{11}{12x}+\frac{1}{4}=\frac{5}{6}\)

\(\frac{11}{12x}=\frac{7}{12}\)

\(x=\frac{11}{12}:\frac{7}{12}\)

\(x=\frac{7}{11}\)

\(\left(-\frac{1}{3}\right)^2+\frac{2}{3x}=\frac{1}{4}\)

\(\frac{1}{9}+\frac{2}{3x}=\frac{1}{4}\)

\(\frac{2}{3x}=\frac{5}{36}\)

\(x=\frac{2}{3}:\frac{5}{36}\)

\(x=\frac{5}{24}\)

\(\left(3x+2\right)^3=\left(-\frac{8}{125}\right)\)

\(\left(3x+2\right)^3=\left(-\frac{2}{5}\right)^3\)

\(\Rightarrow3x+2=-\frac{2}{3}\)

\(3x=-\frac{8}{3}\)

\(x=-\frac{9}{8}\)