$($b$)$ The moment generating function of a random variable $x$ is given by

$M_S(t)=\frac{1}{5}\{\frac{1+2e^{2t}}{e^{4t}}+\frac{e^{3t}+e^{6t}}{e^{5t}}\},$tinR.

Comment on the shape of the distribution of $x$ with measures of skewness and kurtosis.