Question 307330
I'm assuming you meant to write {{{XY^T*Z^T}}}



First off, {{{Y^T}}} is a 3x4 matrix (since the transpose flips the rows and columns). So {{{XY^T}}} is a 2x4 matrix since the product of an m x n and an n x r matrix is an m x r matrix. Also, {{{Z^T}}} is a 4x1 matrix (transposes swap rows and columns). So because {{{XY^T}}} is a 2x4 matrix and {{{Z^T}}} is a 4x1 matrix, this means that {{{XY^T*Z^T}}} is a 2x1 matrix.