(1/3)x+1=(1/3)x
=> x+1=x
=> x-x=-1
=> 0=-1 ( vô lí )
(4/5)x=256/625
=> (4/5)x=(4/5)4
=> x=4
Vậy x=4
a) \(\left(\frac{1}{3}\right)^{x+1}=\left(\frac{1}{3}\right)^x\)
\(\left(\frac{1}{3}\right)^{x+1}-\left(\frac{1}{3}\right)^x=0\)
\(\left(\frac{1}{3}\right)^x.\left[\frac{1}{3}-1\right]=0\)
\(\Leftrightarrow\left(\frac{1}{3}\right)^x=0\) (vô lý)
=> Không có giác trị thõa mãn
b) \(\frac{256}{625}=\frac{4^4}{5^4}=\left(\frac{4}{5}\right)^4\)
\(\left(\frac{1}{3}\right)^{x+1}=\left(\frac{1}{3}\right)^x\)
\(\Leftrightarrow x+1=x\)
\(\Leftrightarrow0=-1\text{(vô lý)}\)
\(\left(\frac{4}{5}\right)^x=\frac{256}{625}\)
\(\Leftrightarrow\left(\frac{4}{5}\right)^x=\left(\frac{4}{5}\right)^4\Leftrightarrow x=4\)
Vậy \(x=4\)
