find unknown value in matrix using matlab
a= 1-b    -1        0;
   -1    3-1.5b    -2;
    0     -2      5-2b
if determinant of matrix a equal zero,then whats the value of b?if the matrix is 6 by 6,then what will be process?please write the instruction in matlab. 
find unknown value in matrix using matlab
===

a= 1-b    -1        0;
   -1    3-1.5b    -2;
    0     -2      5-2b
if determinant of matrix a equal zero,then whats the value of b?if the matrix is 6 by 6,then what will be process?please write the instruction in matlab. 