% Example 10-3: Thickness of a box

W = 15; gamma = 0.101;
V = W/gamma;
% First polynomial: 24-2x
a = [-2  24];
% Second polynomial: 12-2x
b = [-2  12];
% Third polynomial: 4-x
c = [-1   4];
% Mulitply the three polynomials
Vin = conv(c, conv(a, b));
% Form 3rd degree polynomial
p = [0 0 0 (V-24*12*4)] + Vin;
% Find the root
x = roots(p)