Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
(10^2 + 5.10^2 + 5^3):(6^3 + 3. 6^2 + 3^3) = (100 + 500 + 125):(216 + 108 + 27) = 725 : 351 = ... chet cha lon de :D
a) \(\frac{15^5.10^5}{6^6.25^6}\)= (15.10)^5/(6.25)^6=150^5/150^6=1/150
\(^{\frac{\left(5^4-5^3\right)^3}{125^4}=\frac{\left[5^3\cdot\left(5-1\right)\right]^3}{\left(5^3\right)^4}=\frac{\left[5^3\cdot4\right]^3}{5^3\cdot4}=\frac{\left(5^3\right)^3\cdot4^3}{5^{12}}=\frac{5^9\cdot4^3}{5^9\cdot5^3}=\frac{4^3}{5^3}}\)
\(\frac{15^5.10^5}{6^6.25^6}\)
\(=\frac{3^5.5^5.2^5.5^5}{3^6.2^6.5^{12}}\)
\(=\frac{3^5.2^5.5^{10}}{3^6.2^6.5^{12}}\)
\(=\frac{1}{3.2.5^2}\)
\(\frac{\left(5^4.5^3\right)^3}{125^4}\)
\(=\frac{\left(5^7\right)^3}{5^{12}}\)
\(=\frac{5^{21}}{5^{12}}\)
\(=5^9\)
Bài 1:
a) Ta có: \(\dfrac{7^4\cdot3-7^3}{7^4\cdot6-7^3\cdot2}\)
\(=\dfrac{7^3\cdot\left(7\cdot3-1\right)}{7^3\cdot2\left(7\cdot3-1\right)}\)
\(=\dfrac{1}{2}\)
c) Ta có: \(E=1+\dfrac{1}{3}+\dfrac{1}{3^2}+...+\dfrac{1}{3^{100}}\)
\(\Leftrightarrow\dfrac{1}{3}\cdot E=\dfrac{1}{3}+\dfrac{1}{3^2}+\dfrac{1}{3^3}+...+\dfrac{1}{3^{101}}\)
\(\Leftrightarrow E-\dfrac{1}{3}\cdot E=1+\dfrac{1}{3}+\dfrac{1}{3^2}+...+\dfrac{1}{3^{100}}-\left(\dfrac{1}{3}+\dfrac{1}{3^2}+\dfrac{1}{3^3}+...+\dfrac{1}{3^{101}}\right)\)
\(\Leftrightarrow E\cdot\dfrac{2}{3}=1-\dfrac{1}{3^{101}}\)
\(\Leftrightarrow E=\dfrac{3-\dfrac{3}{3^{101}}}{2}=\dfrac{1-\dfrac{1}{3^{100}}}{2}\)