n = -10:0.5:10;
%x = 8*(0.5.^n).*(stepfun(n,-1)-stepfun(n,4));
%or express it as
x = 8*(0.5.^n).*(rectpuls(0.2*n-0.3));
%now transform
g = 8*(0.5.^(-n+4)).*(rectpuls(0.2*(-n+4)-0.3));
stem (n,g);
xlabel('x-axis');
ylabel('y-axis');
title('x[-n+4]');