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\(\frac{\left(\frac{-5}{7}\right)^{n+1}}{\left(\frac{-5}{7}\right)^n}\)
\(=\frac{-5}{7}\)
a: \(=\dfrac{\left(-\dfrac{5}{7}\right)^n}{\left(-\dfrac{5}{7}\right)^n\cdot\dfrac{-7}{5}}=1:\dfrac{-7}{5}=-\dfrac{5}{7}\)
b: \(=\dfrac{\dfrac{1}{4}^n}{\left(-\dfrac{1}{2}\right)^n}=\left(-\dfrac{1}{2}\right)^n\)
a) Ta có: \(\left(0.25\right)^4\cdot1024\)
\(=\left(0.25\right)^4\cdot4^4\cdot4\)
\(=\left(0.25\cdot4\right)^2\cdot4\)
\(=1^2\cdot4=4\)
b) Ta có: \(\frac{230^3}{23^3}\)
\(=\left(\frac{230}{23}\right)^3\)
\(=10^3=1000\)
c) Ta có: \(\frac{\left(-7\right)^n}{\left(-7\right)^{n-1}}\)
\(=\left(-7\right)^n:\left[\frac{\left(-7\right)^n}{-7}\right]\)
\(=\left(-7\right)^n\cdot\frac{-7}{\left(-7\right)^n}\)
\(=-7\)
\(\frac{\left(-\frac{5}{7}\right)^{n+1}}{\left(-\frac{5}{7}\right)^n}=\frac{\left(-\frac{5}{7}\right)^n.\left(-\frac{5}{7}\right)}{\left(-\frac{5}{7}\right)^n}=\frac{-\frac{5}{7}}{1}=-\frac{5}{7}\)
\(\frac{-5}{7}\)