### Transformations

I need help and an explanation for the following: Using the matrix A = 1 -1 0 0 -1 1 -1 2 -1 to compute TsubA(x), for x = (1, 2, 3)^T. Here TsubA: R^3 into R^3 is defined by TsubA(x) = Ax. Also describe the kernel of the transformation TsubA (that is state what a typical vector in ker T looks like).