\(\left(\dfrac{-3}{4}\right)^{3x-1}=\dfrac{256}{81}\)

\(\Rightarrow\left(\dfrac{-3}{4}\right)^{3x-1}=\left(\dfrac{4}{3}\right)^4\)

Xem lại đề

\(\left(-\dfrac{3}{4}\right)3x-1=\dfrac{256}{81}\)

\(-\dfrac{9}{4}\cdot x=\dfrac{337}{81}\)

\(x=\dfrac{337}{81}\cdot-\dfrac{4}{9}\)

\(x=-\dfrac{1348}{729}\)

Sửa đề:

(-3/4)³ˣ⁻¹ = 81/256

(-3/4)³ˣ⁻¹ = (-3/4)⁴

3x - 1 = 4

3x = 4 + 1

3x = 5

x = 5/3

Cách kia hơi lằng nhằng.

Làm lại:

\(\left(-\frac{3}{4}\right)^{3x-1}=\frac{256}{81}=\left(-\frac{3}{4}\right)^{-4}\)

\(\Rightarrow3x-1=-4\)

\(\Rightarrow3x=-3\)

\(\Rightarrow x=-1\)

Ta có : \(\left(-\frac{3}{4}\right)^{-4}=\frac{256}{81}\)

do đó 3x - 1 = -4

=> 3x = -4 + 1 = -3

=> x = -3 : 3 = -1

\(\left(-\frac{3}{4}\right)^{3x-1}=\frac{256}{81}\Rightarrow\left(-\frac{3}{4}\right)^{3x}:\left(-\frac{3}{4}\right)=\frac{256}{81}\Rightarrow\left(-\frac{3}{4}\right)^{3x}=-\frac{64}{27}\Rightarrow\left(-\frac{3^3}{4^4}\right)^x=-\frac{64}{27}\Rightarrow\left(-\frac{27}{64}\right)^x=-\frac{64}{27}\Rightarrow x=-1\)

 dề bài đâu mà tìm?