\[\boxed{\text{988\ (988).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[\text{A\ }( - 6;0)\text{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }B\ (0;12)\]
\[- 6a + 0 = 24,\ \ 0 + 12b = 24\]
\[- 6a = 24\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 12b = 24\]
\[a = - 4\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ b = 2\]
\[Ответ:a = - 4;b = 2.\]