\(d,\left|x-\frac{2}{5}\right|+\frac{1}{2}=\frac{3}{4}\)

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K
Khách

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29 tháng 9 2015

d. \(\left|x-\frac{2}{5}\right|+\frac{1}{2}=\frac{3}{4}\)

             \(\left|x-\frac{2}{5}\right|=\frac{3}{4}-\frac{1}{2}\)

             \(\left|x-\frac{2}{5}\right|=\frac{3-2}{4}\)

             \(\left|x-\frac{2}{5}\right|=\frac{1}{4}\)

Vậy \(x-\frac{2}{5}=\frac{1}{4}\) hoặc \(x-\frac{2}{5}=\frac{-1}{4}\)

\(x-\frac{2}{5}=\frac{1}{4}\)

            \(x=\frac{1}{4}+\frac{2}{5}\)

            \(x=\frac{5+8}{20}\)

            \(x=\frac{13}{20}\)

 

\(x-\frac{2}{5}=\frac{-1}{4}\)

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

            \(x=\frac{-5+8}{20}\)

            \(x=\frac{3}{20}\)

Vậy \(x\in\left\{\frac{13}{20};\frac{3}{20}\right\}\)

29 tháng 9 2015

d) |x-2/5| +1/2 = 3/4

=> |x-2/5| = 1/4

<=> x-2/5 = 1/4 hoặc x=2/5 = -1/4

<=> x=13/20 hoặc 3/20

e) 5/6 -| 2-x| = 1/3

=> |2-x|=1/2

<=> 2-x=1/2 hoặc 2-x=-1/2

<=> x=3/2 hoặc x=5/2

g) làm tương tự

 

15 tháng 6 2019

a/ \(\left(\frac{-2}{3}\right)^4:24=\frac{16}{81}:24=\frac{2}{243}\)

b/ \(\left(\frac{3}{4}\right)^3.4^4=\frac{27}{64}.256=108\)

c/ \(\frac{3.0,8^5}{2,4^4}=\frac{3.0,32768}{33,1776}=\frac{0,98304}{33,1776}=\frac{4}{135}\)

d/ \(\frac{3^3-0,9^5}{2,7^4}=\frac{27-0,59049}{53,1441}=\frac{26,40951}{53,1441}=0,4969415231\)

e/\(\left(\frac{-7}{2}\right)^2+\left(\frac{-3}{4}\right)^3.64-\left(\frac{-61}{5}\right)\)

\(=\frac{49}{4}+\frac{-27}{64}.64+\frac{61}{5}\)

\(=12,25-27+12,2\)

\(=-2,55\)

f/ \(\frac{2^4.2^6}{\left(2^5\right)^2}-\frac{2^5.15^3}{6^3.10^2}=\frac{2^{10}}{2^{10}}-\frac{2^5.5^3.3^3}{2^3.3^3.5^2.2^2}\)

                                      \(=1-\frac{2^5.5^3.3^3}{2^5.3^3.5^2}=1-\frac{5}{1}=-4\)

                                       \(\)

chúc bạn học tốt

Bài 1

\(a,\left(\frac{3}{5}\right)^2-\left[\frac{1}{3}:3-\sqrt{16}.\left(\frac{1}{2}\right)^2\right]-\left(10.12-2014\right)^0\)

\(=\frac{9}{25}-\left[\frac{1}{9}-4.\frac{1}{4}\right]-1\)

\(=\frac{9}{25}-\left(-\frac{8}{9}\right)-1\)

\(=\frac{9}{25}+\frac{8}{9}-1\)

\(=\frac{56}{225}\)

\(b,|-\frac{100}{123}|:\left(\frac{3}{4}+\frac{7}{12}\right)+\frac{23}{123}:\left(\frac{9}{5}-\frac{7}{15}\right)\)

\(=\frac{100}{123}:\left(\frac{4}{3}\right)+\frac{23}{123}:\frac{4}{3}\)

\(=\left(\frac{100}{123}+\frac{23}{123}\right):\frac{4}{3}\)

\(=1:\frac{4}{3}=\frac{3}{4}\)

Phần c đăng riêng vì mk chưa tìm đc cách giải bt mỗi đáp án :v 

\(c,\frac{\left(-5\right)^{32}.20^{43}}{\left(-8\right)^{29}.125^{25}}\)

\(=\frac{\left(-5\right)^{32}.\left(4.5\right)^{43}}{\left[4.\left(-2\right)\right]^{29}.\left(-5^3\right)^{25}}\)

\(=\frac{-5^{32}.4^{43}.5^{43}}{4^{29}.\left(-2\right)^{29}.\left(5\right)^{75}}\)

\(=\frac{\left(-5^4\right)^8.4^{43}.5^{43}}{4^{29}.\left(-2\right)^{29}.\left(5^3\right)^{25}}\)

\(=-\frac{1}{2}\)

20 tháng 7 2018

1.

a)\(\left(x-\frac{1}{2}\right)^2=0\)

\(\Leftrightarrow x-\frac{1}{2}=0\Leftrightarrow x=\frac{1}{2}\)

b)\(\left(x-2\right)^2=1\Leftrightarrow\orbr{\begin{cases}x-2=\sqrt{1}\\x-2=-\sqrt{1}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\sqrt{1}+2\\x=-\sqrt{1}+2\end{cases}}\)

Mấy câu kia tương tự,bạn tự làm nha :)) 

21 tháng 3 2019

a)\(\left(3x-5\right)^{2006}+\left(y^2-1\right)^{2008}+\left(x-z\right)^{2010}=0\)

\(\Leftrightarrow\left(3x-5\right)^{2006}=0\Leftrightarrow3x-5=0\Leftrightarrow x=\frac{5}{3}\)

hay\(\left(y^2-1\right)^{2008}=0\Leftrightarrow y^2-1=0\Leftrightarrow y^2=1\Leftrightarrow y=\pm1\)

hay\(\left(x-z\right)^{2010}=0\Leftrightarrow x-z=0\Leftrightarrow\frac{5}{3}-z=0\Leftrightarrow z=\frac{5}{3}\)

V...\(x=\frac{5}{3},y=\pm1,z=\frac{5}{3}\)

b)Ta co:\(\frac{x}{2}=\frac{y}{3}=\frac{z}{4}\Rightarrow\frac{x^2}{4}=\frac{y^2}{9}=\frac{z^2}{16}=\frac{x^2+y^2+z^2}{4+9+16}=\frac{116}{29}=4\)

Suy ra:\(\frac{x}{2}=4\Leftrightarrow x=8\)

            \(\frac{y}{3}=4\Leftrightarrow y=12\)

             \(\frac{z}{4}=4\Leftrightarrow z=16\)

V...

2 tháng 7 2019

a, \(\frac{-5}{9}.\left(\frac{3}{10}-\frac{2}{5}\right)\)

\(=\frac{-5}{9}.\left(\frac{3}{10}-\frac{4}{10}\right)\)

\(=\frac{-5}{9}.\frac{-1}{10}\)

\(=\frac{5}{90}\)

\(=\frac{1}{18}\)

b,\(\frac{2}{3}+\frac{-1}{3}+\frac{7}{15}\)

\(=\frac{10}{15}-\frac{5}{15}+\frac{7}{15}\)

\(=\frac{12}{15}\)

\(=\frac{4}{5}\)

c, \(\frac{3}{8}.3\frac{1}{3}\)

\(=\frac{3}{8}.\frac{10}{3}\)

\(=\frac{10}{8}\)

\(=\frac{5}{4}\)

d, \(\frac{-3}{5}+0,8.\left(-7\frac{1}{2}\right)\)

\(=\frac{-3}{5}+\frac{4}{5}.\frac{-15}{2}\)

\(=\frac{-3}{5}+\frac{-60}{10}\)

\(=\frac{-3}{5}+\frac{-30}{5}\)

\(=\frac{-33}{5}\)

e, \(\frac{2}{5}.8\frac{1}{3}+1\frac{2}{3}.\frac{2}{5}\)

\(=\frac{2}{5}.\left(8\frac{1}{3}+1\frac{2}{3}\right)\)

\(=\frac{2}{5}.10\)

\(=4\)

f, \(\frac{3}{7}.19\frac{1}{3}-\frac{3}{7}.33\frac{1}{3}\)

\(=\frac{3}{7}.\left(19\frac{1}{3}-33\frac{1}{3}\right)\)

\(=\frac{3}{7}.-14\)

\(=-6\)

~Study well~

#KSJ