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( 12/25 )x = ( 5/3 )-2 - ( -3/5 )4
<=> ( 12/25 )x = 9/25 - 81/625
<=> ( 12/25 )x = 144/625
<=> ( 12/25 )x = ( 12/25 )2
<=> x = 2
Bài làm:
Ta có: \(\left(\frac{12}{25}\right)^x=\left(\frac{5}{3}\right)^{-2}-\left(-\frac{3}{5}\right)^4\)
\(\Leftrightarrow\left(\frac{12}{25}\right)^x=\frac{9}{25}-\frac{81}{625}\)
\(\Rightarrow\left(\frac{12}{25}\right)^x=\frac{144}{625}\)
\(\Leftrightarrow\left(\frac{12}{25}\right)^x=\left(\frac{12}{25}\right)^2\)
\(\Rightarrow x=2\)
\(\left(\frac{12}{25}\right)^x=\left(\frac{5}{3}\right)^{-2}-\left(-\frac{3}{5}\right)^4\)
=> \(\left(\frac{12}{25}\right)^x=\frac{9}{25}-\frac{81}{625}\)
=> \(\left(\frac{12}{25}\right)^x=\frac{225}{625}-\frac{81}{625}=\frac{144}{625}\)
=> \(\left(\frac{12}{25}\right)^x=\left(\frac{12}{25}\right)^2\)
Vậy x = 2
Bài làm :
Ta có :
\(\left(\frac{12}{25}\right)^x=\left(\frac{5}{3}\right)^{-2}-\left(-\frac{3}{5}\right)^4\)
\(\Leftrightarrow\left(\frac{12}{25}\right)^x=\frac{9}{25}-\frac{81}{625}\)
\(\Leftrightarrow\left(\frac{12}{25}\right)^x=\frac{225}{625}-\frac{81}{625}=\frac{144}{625}\)
\(\Leftrightarrow\left(\frac{12}{25}\right)^x=\left(\frac{12}{25}\right)^2\)
\(\Leftrightarrow x=2\)
Vậy x=2
\(a,\left(\frac{3}{8}+-\frac{3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)
= \(\left(-\frac{3}{8}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)
= \(\frac{5}{24}:\frac{5}{6}+\frac{1}{2}\)
= \(\frac{1}{4}+\frac{1}{2}\)
= \(\frac{3}{4}\)
b)\(-\frac{7}{3}.\frac{5}{9}+\frac{4}{9}.\left(-\frac{3}{7}\right)+\frac{17}{7}\)
=\(-\frac{35}{27}+\left(-\frac{4}{21}\right)+\frac{17}{7}\)
= \(-\frac{35}{27}+\frac{47}{21}\)
= \(\frac{178}{189}\)
c) \(\frac{117}{13}-\left(\frac{2}{5}+\frac{57}{13}\right)\)
= \(\frac{117}{13}-\frac{311}{65}\)
= \(\frac{274}{65}\)
d) \(\frac{2}{3}-0,25:\frac{3}{4}+\frac{5}{8}.4\)
= \(\frac{2}{3}-\frac{1}{4}:\frac{3}{4}+\frac{5}{8}.4\)
= \(\frac{2}{3}-\frac{1}{3}+\frac{5}{2}\)
= \(\frac{1}{3}+\frac{5}{2}\)
= \(\frac{17}{6}\)
\(a)\) \(\left|x\right|=\left|x+2\right|=3\)
\(\text{Trường hợp 1:}\)
\(\Leftrightarrow x+x+2=3\)
\(\Leftrightarrow2x=1\)
\(\Leftrightarrow x=\frac{1}{2}\)
\(\text{Trường hợp 2:}\)
\(\Leftrightarrow-x-x-2=3\)
\(\Leftrightarrow-2x=5\)
\(\Leftrightarrow x=-\frac{5}{2}\)
\(b)\) \([\frac{12}{25}.\left(0,75+\frac{7}{4}\right)-1].x=[\frac{7}{5}-\frac{3}{25}.\left(10,6-\frac{3}{5}\right)]\)
\(\Leftrightarrow[\frac{12}{25}.2,5-1].x=[\frac{7}{5}-\frac{3}{25}.10]\)
\(\Leftrightarrow[1,2-1].x=[\frac{7}{5}-2]\)
\(\Leftrightarrow0,2.x=-\frac{3}{5}\)
\(\Leftrightarrow x=-\frac{3}{5}:0,2\)
\(\Leftrightarrow x-3\)