How to solve two step matrix

In mathematics, a matrix (plural matrices) is a rectangular array (see irregular matrix) of numbers, symbols, or expressions, arranged in rows and columns. Provided that they have the same size (each matrix has the same number of rows and the same number of columns as the other), two matrices can be added or subtracted element by element (see conformable matrix). The rule for matrix multiplication, however, is that two matrices can be multiplied only when the number of columns in the first equals the number of rows in the second (i. e., the inner dimensions are the same, n for an (m*n) - matrix times an (n*p) - matrix, resulting in an (m*p) - matrix). There is no product the other way round, a first hint that matrix multiplication is not commutative. Any matrix can be multiplied element-wise by a scalar from its associated field.