Hello Puppeteer,

it is possible, but the number of columns of the left matrix need to be the same than the number of rows at the right one. Or you can use
mat_multiply(float* matrix1,float* matrix2).

look here:
http://de.wikipedia.org/wiki/Matrix_%28Mathematik%29#Matrizenmultiplikation (german)

or here:
http://en.wikipedia.org/wiki/Matrix_%28mathematics%29#Matrix_multiplication.2C_linear_equations_and_linear_transformations
(english)