a: =>(1/2)^4x=(1/2)^10
=>4x=10
=>x=10/4=5/2(loại)
b; \(\Leftrightarrow\dfrac{2^3}{5^2}=\dfrac{2^x}{5^{x-1}}\)
=>x=3 và x-1=2
=>x=3
c: =>(-8/13)^x=(-8/13)^2
=>x=2
d: =>3^x=3
=>3^x=3^1
=>x=1
\(a,\left(\dfrac{1}{16}\right)^x=\left(\dfrac{1}{2}\right)^{10}\\ \Leftrightarrow\left(\dfrac{1}{2}\right)^{4x}=\left(\dfrac{1}{2}\right)^{10}\\\Leftrightarrow4x=10\\ \Leftrightarrow x=2,5\left(loại\right)\\ b,\dfrac{8}{25}=\dfrac{2^x}{5^{x-1}}\\ \Leftrightarrow\dfrac{2^3}{5^2}=\dfrac{2^x}{5^{x-1}}\\ \Leftrightarrow\left\{{}\begin{matrix}x=3\\x=3\end{matrix}\right.\\ \Rightarrow x=3\\ c,\dfrac{64}{169}=\left(-\dfrac{8}{13}\right)^x\\ \Leftrightarrow\left(-\dfrac{8}{13}\right)^2=\left(-\dfrac{8}{13}\right)^x \\ \Leftrightarrow x=2\\ d,9^x:3^x=3\\ \Leftrightarrow\left(9:3\right)^x=3\\ \Leftrightarrow3^x=3^1\\ \Leftrightarrow x=1\)