In Lay is given the following problem:

Suppose the system below is consistent for all possible values offandg. What can you say about the coefficientscandd? Justify your answer.

In the answers is the following:

The row reduction of to

shows thatd-3cmust be nonzero, sincefandgare arbitrary. Otherwise for some choices offandgthe second row could correspond to an equation of the form0=b, wherebis nonzero. Thus .

This is just fine, what I don't understand however is the missing working between the initial matrix and the row reduced version. I can't even figure out which row operations to begin with.

Can someone please explain how this matix:

Row reduces to this:

ty