I would use a loop to create a vector for ‘z’:
x=-2*pi : 2*pi;
y=3*x.*sin(x)-2*x;
y1=3*sin(x)+3*x.*cos(x)-2;
x0 = [-4, -2, 0, 2, 4];
for k1 = 1:numel(x0)
z(k1) = fzero('3*sin(x)+3*x.*cos(x)-2', x0(k1));
end
figure
plot(x,y,'-',x,y1, '--')
hold on
plot(z, zeros(size(z)), 'pg')
hold off
xlabel('\bf\itx-axis\rm')
ylabel('\bf\ity-axis\rm')
legend('y=3xsin(x)-2x','y1=3sin(x)+3xcos(x)-2', 'Location', 'S')
