Row Echelon Form

Reduce $A = \begin{pmatrix} -5 & 5 & 8 \\ 7 & 1 & 4 \\ -8 & 0 & -4 \end{pmatrix}$ to row echelon form. How many non-zero rows remain (i.e. what is the rank of $A$)?

Reduce $A = \begin{pmatrix} 0 & -8 & 2 \\ 0 & 0 & -6 \\ 0 & -10 & 4 \end{pmatrix}$ to row echelon form. How many non-zero rows remain (i.e. what is the rank of $A$)?

The first non-zero entry in a non-zero row is called the: