(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 \(x=4\)

\(\left(\frac{4}{5}\right)\cdot2x=\frac{625}{256}-7\)

\(\left(\frac{4}{5}\right)\cdot2x=-\frac{1167}{256}\)

\(\frac{4}{5}\cdot x=-\frac{1167}{256}\div2\)

\(\frac{4}{5}\cdot x=-\frac{1167}{512}\)

\(x=-\frac{1167}{512}\div\frac{4}{5}\)

\(x=-2,849121094\)

\(\frac{4}{5}\times2x=\frac{625}{256}-7=-\frac{1167}{256}\)
\(\Rightarrow2x=\left(-\frac{1167}{256}\right):\frac{4}{5}=-\frac{5835}{1024}\)
\(\Rightarrow x=\left(-\frac{5835}{1024}\right):2=-2,849121094\)

hình như lộn rồi. x không có giá trị gì hết

-2

Tik cho mk nha..................cảm ơn rất nhiều

256/625=(4/5)⁴

=>2x+7=4

2x=-3

x=-3/2

a.\(3x^2-51=-24\)

\(\Rightarrow3x^2=27\)

\(\Rightarrow x^2=9\)

\(\Rightarrow x=3\)

b.\(5x.\left(5^3\right)^2=625\)

\(\Rightarrow5x=5^5:5^{\left(3x2\right)}\)

\(\Rightarrow5x=5^5:5^6\)

\(\Rightarrow5x=5^{-1}=0,2\)

\(\Rightarrow x=0,2:5\)

\(\Rightarrow x=0,04\)

Mk làm lộn câu b nha.