Find all solutions to the system of equations below, making use of the matrix inverse found in Exercise MISLE.C28. \begin{align*} x_1+x_2+3x_3+x_4&=-4\\ -2x_1-x_2-4x_3-x_4&=4\\ x_1+4x_2+10x_3+2x_4&=-20\\ -2x_1-4x_3+5x_4&=9 \end{align*}