(Solved): a) Solve the following system of linear equations by using the method of substitution. \[ \begin{a ...

a) Solve the following system of linear equations by using the method of substitution. \[ \begin{array}{l} x+3 y=-11 \\ 3 x+2 y=30 \end{array} \] [4 marks] Solve the following system of linear equations by using the method of elimination. \[ \begin{array}{c} 3 x+2 y+9=0 \\ 4 x=3 y+5 \end{array} \] [5 marks] Solve the following equations by using Gaussian elimination. \[ x+y-z=4 \] (i) \( \quad x-2 y+2 z=-5 \) \[ 2 x-y+2 z=-2 \] [8 marks] (ii) \( 2 x+z=7 \) \[ x-2 y+3 z=13 \]