In Sec. 4.11.2, the line for multiplying two matrices together is (obviously) missing a comma. It should have been

c = mult(a, b); // c = a * b

In Sec. 4.11.3, the lines for getting scaling and translation matrices should have been

where (s_x, s_y, s_z) is a scaling vector and (t_x, t_y, t_z) is a translation vector.