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\(\frac{2x+1}{3}=\frac{5}{2}\)
\(2x+1=\frac{5.3}{2}=\frac{15}{2}\)
2x= 15/2 - 1 = 13/2
x = 13/2 : 2
x = 13/4
b) 2x + 2x+1 + 2x+2 + 2x+3 = 480
2x.(1+ 2 +22 + 23) = 480
2x . 15 = 480
2x = 480 : 15 = 32
2x = 25 => x = 5
c) \(\left(\frac{3x}{7}+1\right):\left(-4\right)=-\frac{1}{28}\)
\(\frac{3x}{7}+1=\frac{-1}{28}.\left(-4\right)=\frac{1}{7}\)
\(\frac{3x}{7}=\frac{1}{7}-1=-\frac{6}{7}\)
< = > 3x= -6 => x = -2
minh lam bai nay roi nhung minh ko co nha nen minh ko nho
\(\frac{3x-11}{2}-\frac{x-3}{3}=\frac{1}{6}\)
\(\frac{3\times\left(3x-11\right)}{3\times2}-\frac{2\times\left(x-3\right)}{2\times3}=\frac{1}{6}\)
\(\frac{9x-33}{6}-\frac{2x-6}{6}=\frac{1}{6}\)
\(\frac{\left(9x-33\right)-\left(2x-6\right)}{6}=\frac{1}{6}\)
\(9x-33-2x+6=1\)
\(\left(9x-2x\right)-\left(33-6\right)=1\)
\(7x-27=1\)
\(7x=1+27\)
\(7x=28\)
\(x=\frac{28}{7}\)
\(x=4\)
Chúc bạn học tốt
\(PT\Leftrightarrow\frac{3.\left(3x-11\right)-2.\left(x-3\right)}{6}=\frac{1}{6}\)
<=> 3.(3x - 11) - 2.(x - 3) = 1
<=> 9x - 33 - 2x + 6 = 1
<=> 7x = 28
<=> x = 4
a: \(=\dfrac{17}{4}-\dfrac{37}{100}+\dfrac{1}{8}-\dfrac{32}{25}-\dfrac{5}{2}+\dfrac{7}{2}\)
\(=\dfrac{35}{8}+\dfrac{8}{8}-\dfrac{37}{100}-\dfrac{128}{100}\)
\(=\dfrac{43}{8}-\dfrac{165}{100}=\dfrac{149}{40}\)
b: \(=\left(\dfrac{22\cdot26+3\cdot10-65}{130}\right):\left(\dfrac{4\cdot22-2\cdot26+3\cdot143}{286}\right)\)
\(=\dfrac{537}{130}\cdot\dfrac{286}{465}=\dfrac{1969}{775}\)
a.\(\frac{1}{6}.6^x+6^x.36=6^{15}\left(1+6^3\right)\)
\(6^x.\frac{217}{6}=6^{15}.217\)
\(6^x=6^{16}\)
\(x=16\)
dựa vào bảng ta có khi 7<x<9 thì A<0 vậy 7<x<9
b, ta có : \(\frac{2015}{1}\)+\(\frac{2014}{2}\)+\(\frac{2013}{3}\)+......+\(\frac{1}{2015}\)
=1+1+1+1......+1+\(\frac{2014}{2}\)+\(\frac{2013}{3}\)+.......+\(\frac{1}{2015}\)
(2015 số 1)
=1+(1+\(\frac{2014}{2}\))+(1+\(\frac{2013}{3}\))+........+(1+\(\frac{1}{2015}\))
=\(\frac{2016}{2016}\)+\(\frac{2016}{2}\)+\(\frac{2016}{3}\)+.........+\(\frac{2016}{2015}\)
=2016(\(\frac{1}{2016}\)+\(\frac{1}{2}\)+\(\frac{1}{3}\)+.........+\(\frac{1}{2015}\))