1.Find Three matrices that are row equivalent to?

Question

[4, 3, 7, 5; -1, 2, -1, 3; 2, 0, 1, 4]

Answer 1

Multiplying row (2) by 2 and adding this to row (3) gives:
[ 4 3 7 5 ]
[ -1 2 -1 3 ]
[ 0 4 -1 10]

Multiplying row (2) by 4 and adding this to row (1) gives:
[ 0 11 3 17]
[ -1 2 -1 3]
[ 2 0 1 4]

Multiplying row (3) by -2 and adding to row (1) gives:
[ 0 3 5 -3]
[ -1 2 -1 3]
[ 2 0 1 4]

Each of these three matrices have been obtained by elementary matrix operations, and are thus row equivalent to the given matrix above.