Question

tìm x, biết

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

Answer 1

Ta có: (\(\frac{3}{4}\))^3x-1=\(\frac{256}{81}\)

(\(\frac{3}{4}\))⁴=\(\frac{81}{256}\)\(\Rightarrow\)(\(\frac{3}{4}\))^-4=\(\frac{256}{81}\)

\(\Rightarrow\)3x-1=-4

\(\Rightarrow\)3x=-4+1=-3

\(\Rightarrow\)x=-3:3=-1

Vậy x=-1

Chúc bạn học tốt!

Answer 2

\(\frac{81}{256}\) hay là \(\frac{256}{81}\) vậy bn, có ghi lộn đề ko vậy