1. The problem statement, all variables and given/known data In the following exercises verify that the row rank is equal to the column rank by explicitly finding the dimensions of the row space and the column space of the given matrix. A = [1 2 1 ; 2 1 -1] 2. Relevant equations 3. The attempt at a solution All i can think of is just row reduce it to row echelon form and then find the rank of the matrix. How do i do it explicitly?