You see a picture taken from a linear algebra book where a linear system of equations is presented in the equivalent augmented matrix form. I'm confused about the representation of the first equation in the augmented matrix. What happened to the constant 4? Shouldn't the first row in the matrix be [ 0 -1 -1 1 | -4 ]?
I think its misprinting.
We don't have variable $x_1$ in first row. And we have to write coefficient of $x_1$. That is equal to zero.
But then on right hand side we have -4. So some type of mistake in question.