12p+13q=-24 -4p+6q=-19

12 p + 13 q = -24
-4 p + 6 q = -19

12 p + 13 q = -24
-12 p + 18 q = -57
_____________ _
-5 q = 33
q = - 33/5

72 p + 78 q = 144
-52 p + 78 q = -247
_______________ _
124 p = 391
p = 391/124