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 ?

An idea: The row augmentation on $\;A\;$ is then the same as the product $\;GA\;$. Now, why not using the all important theorem that for any two square matrices $\;X,Y\;$ of the same order we have that $\;\det(XY)=\det X\cdot\det Y\;$ ?
