Đề bài

a) $\left\{ \begin{array}{l}0,5x + 2y =  - 2,5\\0,7x - 3y = 8,1\end{array} \right.$;

b) $\left\{ \begin{array}{l}5x - 3y =  - 2\\14x + 8y = 19\end{array} \right.$;

c) $\left\{ \begin{array}{l}2\left( {x - 2} \right) + 3\left( {1 + y} \right) =  - 2\\3\left( {x - 2} \right) - 2\left( {1 + y} \right) =  - 3\end{array} \right.$.