How to calculate the rank of matrix with parameters?

Question

A = {(b+3; a; 4; -2b-1)(b; -3; 5; -6)(-1; 1; 2a+1; 1-a)}

 

No idea how to solve this, tried everything.. help please! :)

Answer 1

After converting the matrix to a Row echelon form matrix, we will end up with non zero rows with the variables a and b. Unless, we know the actual values of a and b we can determine the excat value for rank of the matrix. At this point there is no assumption of a and b values and the answer for the rank of the matrix is 3.