A matrix is in Reduced Row Echelon Form (RREF) if it satisfies:

• All zero rows are at the bottom
• The first non-zero entry in each row (pivot) is 1
• Each pivot is to the right of the pivot in the row above
• Each pivot is the only non-zero entry in its column

Uses:

• Solving systems of linear equations $Ax = b$
• Finding the rank of a matrix
• Determining linear independence of vectors
• Finding basis for row space and null space