Can't plot on MATLAB

Question

clear;
for R=3:18
    x=inv([9 119 0 0 0;
        0 16*R+8 -8 0 0;
        -1 -15 0 -4 4;
        -8 -148 0 40 0;
        0 -1 1 0 0])*[-40;
        0;
        0;