PLS HELP! ITS WORTH 25 POINTS

Solve the system using elimination:

-3x - 3y = 12
-9x + 3y = -24

Solve the system using elimination:

-5x + 3y = 2
-5x - 5y = -30

Solve the system using elimination:

12x - 8y = -12
6x + 4y = -30