Systems Ib.
Task number: 2383
Solve the following system of equations.
Variant 1
\( \begin{array}{rrrrrr} 17 a& +9 b& -9 c& +3d&=& -8 \\ 11 a& & +2 c& &=& -7 \\ 13 a& +2 b& - c& &=& -9 \\ 7 a& +3 b& -5 c& + d&=& -8 \end{array} \)
Variant 2
\( \begin{array}{rrrrrr} 17 a& +8 b& +4 c& +7d&=& 30 \\ -11 a& & & +3d &=& -2 \\ 7 a& +2 b& + c& -2d &=& -1 \\ 13 a& +6 b& & -2d&=& 7 \end{array} \)