Exercise 4.2.3

Let $A=\left[\begin{array}{rrr}1&2&-1\\ -1&4&0\\ \end{array}\right]$ and $B=\left[\begin{array}{rrr}0&3&0\\ 1&-1&1\\ \end{array}\right]$.

Find a matrix $X$ such that $(A+X)-(B+0)=B+A$. Hint: first use the properties of matrix addition to simplify the equation and solve for $X$.