dài thế bạn

A) -2/5

B) -1

C) 2/5

D) 39/64

$\textbf{a)}$

$\left(\dfrac23\right)^3:\left(-\dfrac13\right)^5$

$=\dfrac{2^3}{3^3}:\left(-\dfrac1{3^5}\right)$

$=\dfrac8{27}\cdot(-243)$

$=-72.$

$\textbf{b)}$

$\left(\dfrac57\right)^6:\left(-\dfrac{25}{49}\right)^3$

$=\left(\dfrac57\right)^6:\left(-\left(\dfrac57\right)^2\right)^3$

$=\left(\dfrac57\right)^6:\left(-\left(\dfrac57\right)^6\right)$

$=-1.$

a, \(\frac{13.2-13.3}{1-27}\)=\(\frac{13.\left(2-3\right)}{-26}\)=\(\frac{13.\left(-1\right)}{-26}\)=\(\frac{-13}{-26}\)=\(\frac{1}{2}\)

b,\(\frac{15.\left(-3\right)+23.15}{-5+20}\)=\(\frac{15.[\left(-3\right)+23]}{15}\)=\(\frac{15.20}{15}\)=\(\frac{300}{15}\)=20

Chúc bạn học tốt

ý B hình như mk giải rồi thì phải

\(A=\frac{a^2.a^7.b^2.c^8}{a^5.b^3.\left(-c\right)^4}=\frac{a^9.b^2.c^8}{a^5.b^3.c^4}=\frac{a^4.c^4}{b}\)

\(B=\left(\frac{3}{7}\right)^5.\frac{\left(25\right)^4.7^5}{15^4.20^2}=\frac{3^5.\left(5^2\right)^4.7^5}{7^5.\left(3.5\right)^4.\left(4.5\right)^2}=\frac{3^5.5^8.7^5}{7^5.3^4.5^4.4^2.5^2}\)

    \(=\frac{3^5.5^8.7^5}{7^5.3^4.5^6.4^2}=\frac{3.5^2}{4^2}=\frac{75}{16}\)

a: \(\frac{4^{30}\cdot3^{43}}{2^{53}\cdot27^{15}}\)

\(=\frac{\left(2^2\right)^{30}\cdot3^{43}}{2^{53}\cdot\left(3^3\right)^{15}}\)

\(=\frac{2^{60}}{2^{53}}\cdot\frac{3^{43}}{3^{45}}=\frac{2^7}{3^2}=\frac{128}{9}\)

b: \(\left(-27\right)^{10}\cdot16^{25}\)

\(=-3^{30}\cdot\left(2^4\right)^{25}=-3^{30}\cdot2^{100}\)

\(6^{30}\cdot\left(-32\right)^{15}\)

\(=2^{30}\cdot3^{30}\cdot\left(-1\right)\cdot\left(2^5\right)^{15}=-2^{105}\cdot3^{30}\)

\(\frac{\left(-27\right)^{10}\cdot16^{25}}{6^{30}\cdot\left(-32\right)^{15}}\)

\(=\frac{-2^{100}\cdot3^{30}}{-2^{105}\cdot3^{30}}=\frac{1}{2^5}=\frac{1}{32}\)

c: \(\left(-\frac{2}{17}\right)^3\cdot\left(-\frac{17}{35}\right)^3\cdot\left(\frac{35}{3}\right)^3\)

\(=\left(-\frac{2}{17}\cdot\frac{-17}{35}\cdot\frac{35}{3}\right)^3\)

\(=\left(\frac23\right)^3=\frac{8}{27}\)

e: \(2^2+4^2+\cdots+24^2\)

\(=2^2\left(1^2+2^2+\cdots+12^2\right)\)

\(=4\cdot650=2600\)

a: ĐKXĐ: \(x\notin\left\{0;5;-5\right\}\)

b: \(P=\left(\dfrac{x}{\left(x-5\right)\left(x+5\right)}-\dfrac{x-5}{x\left(x+5\right)}\right):\left(\dfrac{10x-25}{x\left(x+5\right)}-\dfrac{x}{x-5}\right)\)

\(=\dfrac{x^2-x^2+10x-25}{x\left(x-5\right)\left(x+5\right)}:\dfrac{\left(10x-25\right)\left(x-5\right)-x^2\left(x+5\right)}{x\left(x+5\right)\left(x-5\right)}\)

\(=\dfrac{10x-25}{10x^2-50x-25x+125-x^3-5x^2}\)

\(=\dfrac{10x-25}{-x^3+5x^2-75x+125}\)

\(\frac{\left(-30\right)\left(-5\right)\cdot3}{6\cdot25\cdot8}\Leftrightarrow\frac{30\cdot5\cdot3}{6\cdot25\cdot8}\)

\(\Rightarrow\frac{6\cdot5\cdot5\cdot3}{6\cdot5\cdot5\cdot8}=\frac{3}{8}\)