Answer:
x = 25/3; y = -5/3
Step-by-step explanation:
You did well so far by multiplying both sides of the first equation by 2.
Now notice that you have -2y in the new first equation and 2y in the second equation. -2y and 2y add to 0.
Now add the equations to eliminate y.
2x - 2y = 20
(+) 4x + 2y = 30
-------------------------
6x = 50
6x/6 = 50/6
x = 50/6 = 25/3
2x - 2y = 20
2(25/3) - 2y = 20
50/3 - 2y = 60/3
-2y = 60/3 - 50/3
-2y = 10/3
-2y/2 = (10/3)/(-2)
y = -5/3
Solution: x = 25/3; y = -5/3
