Answer :
I would go about solving this by elimination because the x variables are already the same so all you would have to do is change one equation to the opposite signs and add them, so it would look like:
7y + 5x = 19
+ -3y - 5x = -7
-------------------
4y=12
y=3
7y + 5x = 19
+ -3y - 5x = -7
-------------------
4y=12
y=3
7y + 5x = 19 ⇒ 21y + 15x = 57
3y + 5x = 7 ⇒ 21y + 21x = 49
-6x = 8
-6 -6
x = -1 1/3
7y + 5x = 19
7y + 5(-1 1/3) = 19
7y - 6 2/3 = 19
+6 2/3 +6 2/3
7y = 25 2/3
7 7
y = 3 2/3
(x, y) = (-1 1/3, 3 2/3)
3y + 5x = 7 ⇒ 21y + 21x = 49
-6x = 8
-6 -6
x = -1 1/3
7y + 5x = 19
7y + 5(-1 1/3) = 19
7y - 6 2/3 = 19
+6 2/3 +6 2/3
7y = 25 2/3
7 7
y = 3 2/3
(x, y) = (-1 1/3, 3 2/3)