$6\mathrm{.}3$ Use a Fourier transform table and properties of the Fourier transform to find the Fourier transform $x$ of each function $x$ below.

$($a$)x(t)=cos(t-5)$;

$($b$)x(t)=e^{-j5t}u(t+2)$;

$($c$)x(t)=cos(t)u(t)$;

$($d$)x(t)=6[u(t)-u(t-3)]$;

$6\mathrm{.}3$ a$-$d $[$Tables$]$