Question

find the rank of the matrix
3 0 2 2
-6 42 24 54
21 -21 0 -15

Answer 1

convert it to echelon form

Answer 2

by Gaussian elimination method

Answer 3

thanks aajugdar.....

Answer 4

then you can easily find the rank
a rank is counted as row/column which has non zero elements
then the 1 which is not proportional or identical to other
and if its not linear combination of other 2 rows/columns