a, \(\left(\dfrac{3}{4}\right)^5x=\left(\dfrac{3}{4}\right)^7\Rightarrow x=\left(\dfrac{3}{4}\right)^7:\left(\dfrac{3}{4}\right)^5=\left(\dfrac{3}{4}\right)^2=\dfrac{9}{16}\)
b, \(\left(x-1\right)^3=27=3^3\Rightarrow x-1=3\Leftrightarrow x=4\)
c, \(\dfrac{64}{4^{x+1}}=4\Leftrightarrow\dfrac{4^3}{4^{x+1}}=4\Leftrightarrow4^{3-\left(x+1\right)}=4\Leftrightarrow4^{2-x}=4\Rightarrow2-x=1\Leftrightarrow x=1\)
d, \(\left(-2\right)^x=4^5.16^2=2^{10}.2^{2^8}=2^{18}=\left(-2\right)^{18}\Rightarrow x=18\)
e, \(\left(x-1\right)^3=-125=\left(-5\right)^3\Rightarrow x-1=-5\Leftrightarrow x=-4\)
f, \(\left(\dfrac{9}{5}-x\right)^2=\dfrac{16}{25}=\left(\dfrac{4}{5}\right)^2\)
TH1 : \(\dfrac{9}{5}-x=\dfrac{4}{5}\Leftrightarrow x=1\)
TH2 : \(\dfrac{9}{5}-x=-\dfrac{4}{5}\Leftrightarrow x=\dfrac{13}{5}\)
