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a) \(\dfrac{\left(-3\right)^{10}\cdot15^5}{25^3\cdot\left(-9\right)^7}\)

\(=-\dfrac{3^{10}\cdot3^5\cdot5^5}{5^6\cdot3^{14}}\)

\(=\dfrac{-3}{5}\)

b: \(\dfrac{4^{30}\cdot3^{43}}{2^{57}\cdot27^{15}}\)

\(=\dfrac{2^{60}\cdot3^{43}}{2^{57}\cdot3^{45}}\)

\(=8\cdot\dfrac{1}{9}=\dfrac{8}{9}\)

24 tháng 12 2017

\(\dfrac{40^{30}.3^{43}}{2^{57}.27^{15}}=\dfrac{\left(2^3.5\right)^{30}.3^{43}}{2^{57}.\left(3^3\right)^{15}}=\dfrac{2^{90}.5^{30}.3^{43}}{2^{57}.3^{45}}\)

\(=\dfrac{2^{33}.2^{57}.5^{30}.3^{43}}{2^{57}.3^{43}.3^2}=\dfrac{2^{33}.5^{30}}{3^2}=\dfrac{2^{33}.5^{30}}{9}\)

24 tháng 12 2017

bạn gì kết quả to lắm nên mình chỉ để như vậy thôi

haha

11 tháng 8 2018

\(A=\frac{-2}{9}+\frac{-3}{4}+\frac{3}{5}+\frac{1}{15}+\frac{1}{57}+\frac{1}{3}+\frac{-1}{36}\)

\(A=\left(\frac{-2}{9}+\frac{-3}{4}+\frac{1}{3}+\frac{-1}{36}\right)+\left(\frac{3}{5}+\frac{1}{15}\right)+\frac{1}{57}\)

\(A=\left(\frac{-8}{36}+\frac{-27}{36}+\frac{12}{36}+\frac{-1}{36}\right)+\left(\frac{9}{15}+\frac{1}{15}\right)+\frac{1}{57}\)

\(A=\frac{-2}{3}+\frac{2}{3}+\frac{1}{57}\)

\(A=\frac{-38}{57}+\frac{38}{57}+\frac{1}{57}\)

\(A=\frac{1}{57}\)

13 tháng 8 2018

Do x2n=(-x)2n

=>327.1530.(-4)16=327.(-15)30.416=327.(-15)30.(42)8=327.(-15)30.88

(327.1530.(-4)16​)/(​​(-15)30.811)=(327.(-15)30.88)/(​​(-15)30.811)=327/83

a) Ta có: \(\left(x-1\right)^{x+2}-\left(x-1\right)^{x+4}=0\)

\(\Leftrightarrow\left(x-1\right)^x\cdot\left(x-1\right)^2-\left(x-1\right)^x\cdot\left(x-1\right)^4=0\)

\(\Leftrightarrow\left(x-1\right)^{x+2}\cdot\left[1-\left(x-1\right)^2\right]=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x-1=1\\x-1=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\\x=0\end{matrix}\right.\)

b) Ta có: \(\dfrac{1}{4}\cdot\dfrac{2}{6}\cdot\dfrac{3}{8}\cdot\dfrac{4}{10}\cdot\dfrac{5}{15}\cdot...\cdot\dfrac{30}{62}\cdot\dfrac{31}{64}=2x\)

\(\Leftrightarrow2x=\dfrac{1}{64}\)

hay \(x=\dfrac{1}{128}\)