\(\frac{\left(-3\right)^x}{81}=-27\\ \Leftrightarrow\left(-3\right)^x=-27.81\\ \Leftrightarrow\left(-3\right)^x=-2187\\ \Leftrightarrow\left(-3\right)^x=\left(-3\right)^7\\ \Rightarrow x=7\)
đề là \(\left(-3\right)^{\frac{x}{81}}\)=-27 hở bạn
(-3)^x/81 = -27
=>(-3)^x/81 = (-3)^3
=>x/81 = 3
=>x = 3.81 = 243
\(\frac{\left(-3\right)^x}{81}\)=-27
⇔\(\left(-3\right)^x\)=-27.81
⇔\(\left(-3\right)^x\)=-2187
⇔\(\left(-3\right)^x\)=\(\left(-3\right)^7\)
⇒ x=7
Vậy ....
