To compute row reductions, feel free to use numerical applets such as this one from Georgia Tech, but make sure to state which row operations you have done, and to write the resulting matrix of each row operation.

Section 3.1: 8, 10, 12

Section 3.2: 13, 14 (hint for 3.2.14: do row reduction on the block matrix \( D \), and separate into two cases, when \( D \) is singular and when it is invertible.)

Section 3.3: 1(b,d), 2(b), 3(b), 6, 8 (for problem 3.3.1, expand only to first order, i.e. write the determinant in terms of determinants of \( 3\times 3 \) submatrices)

Section 3.4: 1(b,d), 2(b,d)