Answer
$x=0$
Work Step by Step
Apply $\log$ to both sides and then isolate $x$ as follows:
$\log (1.2^{x})=\log(0.5)^{-x} \\ x\log(1.2)=-x\log(0.5) \\ x\log(1.2)+x\log(0.5)=0 \\ x [\log(1.2)+\log(0.5)]=0 \\ x=0$
Thus, our answer is: $x=0$