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7 tháng 8 2018

TÍNH NHÉ

7 tháng 8 2018

\(-\frac{3}{8}-\left(-\frac{1}{2}\right)^2-0,25\)

\(=-\frac{3}{8}-\frac{1}{4}-\frac{1}{4}\)

\(=-\frac{3}{8}-\frac{2}{4}=-\frac{3}{8}-\frac{1}{2}\)

\(=-\frac{3}{8}-\frac{4}{8}=\frac{-7}{8}\)

15 tháng 8 2023

cho mình xin đề bài

 

15 tháng 4 2019

\(0,25.2\frac{1}{3}.30.0,5.\frac{8}{45}\)

\(=\frac{1}{4}.\frac{7}{3}.30.\frac{1}{2}.\frac{8}{45}\)

\(=\frac{14}{9}\)

15 tháng 4 2019

\(0,25.2\frac{1}{3}.30.0,5.\frac{8}{45}\)

\(=0,25.\frac{7}{3}.30.0,5.\frac{8}{45}\)

\(=\frac{7}{12}.30.\frac{4}{45}\)

\(\frac{35}{2}.\frac{4}{45}\)

\(=\frac{14}{9}\)

1) Ta có: \(\left(-\dfrac{2}{3}\right)^2\cdot\dfrac{-9}{8}-25\%\cdot\dfrac{-16}{5}\)

\(=\dfrac{4}{9}\cdot\dfrac{-9}{8}-\dfrac{1}{4}\cdot\dfrac{-16}{5}\)

\(=\dfrac{-1}{2}+\dfrac{4}{5}\)

\(=\dfrac{-5}{10}+\dfrac{8}{10}=\dfrac{3}{10}\)

2) Ta có: \(-1\dfrac{2}{5}\cdot75\%+\dfrac{-7}{5}\cdot25\%\)

\(=\dfrac{-7}{5}\cdot\dfrac{3}{4}+\dfrac{-7}{5}\cdot\dfrac{1}{4}\)

\(=\dfrac{-7}{5}\left(\dfrac{3}{4}+\dfrac{1}{4}\right)=-\dfrac{7}{5}\)

3) Ta có: \(-2\dfrac{3}{7}\cdot\left(-125\%\right)+\dfrac{-17}{7}\cdot25\%\)

\(=\dfrac{-17}{7}\cdot\dfrac{-5}{4}+\dfrac{-17}{7}\cdot\dfrac{1}{4}\)

\(=\dfrac{-17}{7}\cdot\left(\dfrac{-5}{4}+\dfrac{1}{4}\right)\)

\(=\dfrac{17}{7}\)

4) Ta có: \(\left(-2\right)^3\cdot\left(\dfrac{3}{4}\cdot0.25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)

\(=\left(-8\right)\cdot\left(\dfrac{3}{4}\cdot\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)

\(=\left(-8\right)\cdot\dfrac{3}{16}:\dfrac{54-28}{24}\)

\(=\dfrac{-3}{2}\cdot\dfrac{24}{26}\)

\(=\dfrac{-72}{52}=\dfrac{-18}{13}\)

21 tháng 8 2017

\(x^2-0,25=0\)

\(\Leftrightarrow x^2-0,5^2=0\)

\(\Leftrightarrow x-0,5=0\)

\(\Leftrightarrow x=0+0,5\)

\(\Leftrightarrow x=0,5\)

b.

\(\dfrac{8}{2x}=2\Leftrightarrow2x=\dfrac{8}{2}\Rightarrow x=4:2=2\)

c.

\(\left(2x-1\right)^3=8\)

\(\Rightarrow\left(2x-1\right)^3=2^3\)

\(\Rightarrow2x-1=2\)

\(\Rightarrow2x=2+1\)

\(\Rightarrow2x=3\)

\(\Rightarrow x=\dfrac{3}{2}\)

d.

\(\left(x-2\right)^2=16\)
\(\Rightarrow\left(x-2\right)^2=4^2\)

\(\Rightarrow x-2=4\)

\(\Rightarrow x=4+2\)

\(\Rightarrow x=6\)

Chúc bạn học tốt!!!!

21 tháng 8 2017

\(x^2-0,25=0\)

\(\Rightarrow x^2=0,25\)

\(\Rightarrow x=0,5\)

b. \(\dfrac{8}{2x}=2\)

\(\Rightarrow2x=4\)

\(\Rightarrow x=2\)

c. \(\left(2x-1\right)^3=8\)

\(\left(2x-1\right)^3=2^3\)

\(\Rightarrow2x-1=2\)

\(\Rightarrow x=\dfrac{3}{2}\)

d. \(\left(x-2\right)^2=16\)

\(\left(x-2\right)^2=\pm4^2\)

\(\Rightarrow\left[{}\begin{matrix}x-2=4\\x-2=-4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\)

8 tháng 11 2016

32+-1/8+1/4

257/8

18 tháng 4 2023

`(x-5/12)^2 : 1 1/3= 0,25`

`=> (x-5/12)^2 : 4/3 = 0,25`

`=> (x-5/12)^2 =0,25 . 4/3`

`=> (x-5/12)^2 =1/3`

`=> (x-5/12)^2 =` \(\pm\left(\dfrac{1}{\sqrt{3}}\right)^2\)

\(\Rightarrow\left[{}\begin{matrix}x-\dfrac{5}{12}=\dfrac{1}{\sqrt{3}}\\x-\dfrac{5}{12}=-\dfrac{1}{\sqrt{3}}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{\sqrt{3}}+\dfrac{5}{12}\\x=-\dfrac{1}{\sqrt{3}}+\dfrac{5}{12}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{5+4\sqrt{3}}{12}\\x=\dfrac{5-4\sqrt{3}}{12}\end{matrix}\right.\)

`@ Yamada-Akiro`

7 tháng 4 2019

\(\left(-6,17+3\frac{5}{9}-2\frac{36}{97}\right).\left(\frac{1}{3}-0,25-\frac{1}{12}\right)\)

\(=\left(-6,17+\frac{32}{9}-\frac{230}{97}\right).\left(\frac{1}{3}-\frac{1}{4}-\frac{1}{12}\right)\)

\(=\left(-6,17+\frac{32}{9}-\frac{230}{97}\right).\left(\frac{4}{12}-\frac{3}{12}-\frac{1}{12}\right)\)

\(=-4,985578465.0\)

\(=0\)

P/s: Hoq chắc :((