(Solved): can you check my work please. if wrong please solve, thank you!  Use Substitution or Eliminatio ...

Use Substitution or Elimination to solve for \( x \) and \( y \). (Write your answer as an ordered pair.) a. \[ \begin{array}{l} \begin{array}{l|l} -3 y & =12 \\ y & =-4 \end{array} \quad \begin{array}{l} x+2(-4)=-1 \\ x-8=-1 \end{array} \\ \end{array} \] b. \[ \begin{array}{cc} 6 x-4 y=3 & 18 x-12 y=9 \\ -18 x+12 y=-9 & 18 x+12 y=-9 \\ -18=0 \end{array} \] c. \( 3 x-5 y=4 \) \( -15 x+25 y=20 \) Infinite Many