Given equation is

7 x -9 y = 19

9y = 7 x -19

y = (7 x -19) / 9

y = (7/9) x + (-19/9)

y=mx+b form of given equation is y = (7/9) x + (-19/9)

The ordered pair that lies on this line when x =-18 is y

So Substitute x =-18 in given equaton y = (7/9) x + (-19/9)

y = (7/9) (-18) + (-19/9)

y = 7*(-2) + (-19/9)

y = -14 + (-19/9)

y = (-14*9-19)/9

y = (-126-19)/9

y = (-145)/9

y = -16.11

Ordered pair is ( -18 , -16.11)