Determine the z-transform of the following sequences using the z-transform table and the z-transform properties. Express X(z) as a rational function in z^-1. Verify your results using MATLAB. Indicate the region of convergence in each case, and provide a pole-zero plot.
a) x(n) = 2δ(n - 2) + 3u(n - 3)
b) x(n) = 3(0.75)^n cos(0.3Ď€ n)u(n) + 4(0.75)^n sin(0.3Ď€ n)u(n)