if you multiply the top equation by -2 you get:
-4x -14y = 14 => -4x = 14+14y
now you can plug in the -4x into the second equation:
14+14y - 3y = -19 => 11y = -33 => y=-3
Fill in y=-3 in either equation to find x:
2x - 21 = -7 => 2x = 14 => x=7
So your ordered pair is (7,-3)