Effect of row augmentation on value of determinant. 
Part(a) is done.
How to proceed for part (b).
My first question is what do they mean by row augmentation ?
Do they mean the row operation of adding k times the first row to third by row augmentation ?

Here are three relevant rules determinant manipulation:
Let $A$ be a square matrix. Let $B$ be made from $A$ by
$(1)$ Multiplication of a row of $A$ with a scalar $c$; then $\det B = c\det A$.

$(2)$ Swapping two rows; then $\det B = -\det A$.

$(3)$ Adding a multiplum of a row to another row; then $\det B = \det A$.
Which one is relevant for you?
