a) Vì \(\left(2.x+3\right)^2=\dfrac{9}{121}\Rightarrow\left\{{}\begin{matrix}2.x+3=\dfrac{3}{11}\\2.x+3=-\dfrac{3}{11}\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=-\dfrac{15}{11}\\x=-\dfrac{18}{11}\end{matrix}\right.\)
b) Vì \(\left(3.x-1\right)^3=-\dfrac{8}{27}\Rightarrow3.x-1=-\dfrac{2}{3}\Rightarrow x=\dfrac{1}{9}\)
\(\left(2x+3\right)^2=\frac{9}{121}\\ \left(3x-1\right)^3=-\frac{8}{27}\)
\(\left(\dfrac{1}{8}\right)^{x^{ }}.27^{2x}=\left(-9\right)^4\)
Tìm các số tự nhiên m,n biết :
a) \(\left(-\dfrac{1}{5^{ }}\right)^n\) =\(-\dfrac{1}{125}\)
b)\(\left(-\dfrac{2}{11^{ }}\right)^m=\dfrac{4}{121}\)
c)\(7^{2n}+7^{2n+2}=2450\)
Rút gọn:
a) \(\dfrac{2^{19}\cdot27^3+15\cdot4^9\cdot9^4}{6^9\cdot2^{10}+2^{10}}\)
b) \(\dfrac{\left(-\dfrac{1}{2}\right)^3-\left(\dfrac{3}{4}\right)^3\cdot\left(-2\right)^2}{2\cdot\left(-1\right)+\left(\dfrac{3}{4}\right)^2-\left(\dfrac{3}{8}\right)}\)
tìm x biết
a) \(\dfrac{2}{5}-\left(\dfrac{1}{10}-x\right)=\left(\dfrac{-2}{5}-\dfrac{1}{2}\right)^2\)
b) \(\dfrac{2}{5}-\dfrac{3}{5}\left(x-2\right)=\left(\dfrac{-1}{2}\right)^3-\left(\dfrac{3}{4}\right)^3.\left(-2\right)^2\)
BT4:Tìm x, biết:
a) \(x\div\left(\dfrac{3}{4}\right)^3=\left(\dfrac{3}{4}\right)^2\)
b) \(\left(\dfrac{2}{5}\right)^5\div x=\left(\dfrac{2}{5}\right)^8\)
Tìm x, biết:
a) x : \(\left(\dfrac{3}{4}\right)^3\)= \(\left(\dfrac{3}{4}\right)^2\) b) \(\left(\dfrac{2}{5}\right)^5\). x = \(\left(\dfrac{2}{5}\right)^8\)
1: Tính : \(\dfrac{\left(\dfrac{2}{5}\right)^7.5^7+\left(\dfrac{9}{4}\right)^3:\left(\dfrac{3}{16}\right)^3}{2^7.5^2+512}\) 2 . Tìm x biết :\(\left(5.x+1\right)^2=\dfrac{36}{49}\)
Bài 1: Tìm x:
\(\left(x+\dfrac{2}{3}\right)^5=\left(x+\dfrac{2}{5}\right)^3\)
Bài 2: Tìm x,y\(\in\) N biết:
\(\dfrac{27^x}{3^{2x-y}}=243\) và \(\dfrac{25^x}{5^{x+y}}=125\)
