108

Đúng ko

K mk nhé

*Mio*

 3 + 5 . 21 = 3 + 105 = 108

\(=\frac{3^7\cdot\left(2^4\right)^3}{\left(2^2\cdot3\right)^5\cdot\left(3^3\right)^2}\)    

\(=\frac{3^7\cdot2^{12}}{2^{10}\cdot3^5\cdot3^6}\)    

\(=\frac{3^7\cdot2^{12}}{2^{10}\cdot3^{11}}\)   

\(=\frac{2^2}{3^4}\)   

\(=\frac{4}{81}\)

\(\frac{3^7.16^3}{12^5.27^2}=\frac{3^7.\left(2^4\right)^3}{\left(2^2.3\right)^5.\left(3^3\right)^2}=\frac{3^7.2^{12}}{2^{10}.3^5.3^6}=\frac{3^7.2^{12}}{2^{10}.3^{11}}=\frac{2^2}{3^4}=\frac{4}{81}\)

\(\frac{3^7.16^3}{12^5.27^2}=\frac{3^7.\left(2^4\right)^3}{\left(2^2.3\right)^5.\left(3^3\right)^2}=\frac{3^7.2^{12}}{2^{10}.3^{11}}=\frac{2^2}{3^4}\)

a)\(=\frac{\left(-0,3\right)^7.2^8}{\left(-0,3\right)^7.2^7.\left(-1\right)}\)

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

b)\(=\frac{3^7.2^{12}}{2^{10}.3^{11}}\)

\(=\frac{2^2}{3^4}=\frac{4}{81}\)

khó quá tui ko biết làm..

k cho tui nha

thanks

a,     4x - 15 = ( -75 ) - x

<=> 4x +x = -75 + 15

<=> 5x = -60

<=> x = -12

b,     72 - 3x = 5x +8

<=>  72 - 8 = 5x + 3x 

<=> 8x = 64

<=> x = 8

c,  3.|x-7| = 21

* Nếu x - 7 \(\ge\)0 <=> x \(\ge\)7 thì

      PT <=> 3 .( x- 7 ) = 21

            <=> x - 7 = 7

            <=>  x = 14 ( tm )

* Nếu x < 7 <=> x < 7 thì 

     PT <=> 3. [ - ( x- 7 ) ] = 21

           <=> -x +7 = 7

           <=> -x = 0

           <=> x = 0 ( tm )

d,   \(-7.|x+3|=-49\).

\(\Leftrightarrow|x+3|=7\)

\(\Leftrightarrow\orbr{\begin{cases}x+3=7\\x+3=-7\end{cases}\Leftrightarrow\orbr{\begin{cases}x=4\\x=-10\end{cases}}}\)

e, c-12.(x-5)+7.(3-x)=5

<=> -12x + 60 + 21 - 7x = 5

<=> -19x + 81 = 5

<=> -19x = -76

<=> x = 4

\(\frac{2^{19}\cdot27^4}{6^7\cdot16^3}\)

\(=\frac{2^{19}\cdot3^{12}}{2^7\cdot3^7\cdot2^{12}}\)

\(=\frac{2^{19}\cdot3^{12}}{2^{19}\cdot3^7}\)

\(=3^5\)

\(=243\)

\(\frac{2^{19}.27^4}{6^7.16^3}\)

\(=\frac{2^{19}.\left(3^3\right)^4}{2^7.3^7.\left(2^4\right)^3}\)

\(=\frac{2^{19}.3^{12}}{2^7.3^7.2^{12}}\)

=\(3^5=243\)

Ta có:\(\frac{x-1}{2013}+\frac{x-2}{2012}=\frac{x-3}{2011}+\frac{x-4}{2010}\)

\(\Rightarrow\left(\frac{x-1}{2013}-1\right)+\left(\frac{x-2}{2012}-1\right)=\left(\frac{x-3}{2011}-1\right)+\left(\frac{x-4}{2010}-1\right)\)

\(\Rightarrow\frac{x-2014}{2013}+\frac{x-2014}{2012}=\frac{x-2014}{2011}+\frac{x-2014}{2010}\)

\(\Rightarrow\frac{x-2014}{2013}+\frac{x-2014}{2012}-\frac{x-2014}{2011}-\frac{x-2014}{2010}=0\)

\(\Rightarrow\left(x-2014\right).\left(\frac{1}{2013}+\frac{1}{2012}-\frac{1}{2011}-\frac{1}{2010}\right)=0\)

Vì \(\frac{1}{2013}+\frac{1}{2012}-\frac{1}{2011}-\frac{1}{2010}\ne0\)nên để biểu thức =0 

\(\Leftrightarrow x-2014=0\Rightarrow x=2014\)

Ta cTa có: 2013 x − 1 + 2012 x − 2 = 2011 x − 3 + 2010 x − 4 ⇒ 2013 x − 1 − 1 + 2012 x − 2 − 1 = 2011 x − 3 − 1 + 2010 x − 4 − 1 ⇒ 2013 x − 2014 + 2012 x − 2014 = 2011 x − 2014 + 2010 x − 2014 ⇒ 2013 x − 2014 + 2012 x − 2014 − 2011 x − 2014 − 2010 x − 2014 = 0 ⇒ x − 2014 . 2013 1 + 2012 1 − 2011 1 − 2010 1 = 0 
1 = 0

chúc bn hok tốt @_@