Question

What is the value of the y variable in the solution to the following system of equations?

3x + y = 11
–3x + 2y = 1

Answer 1

Solution:
We can add both of these equations together as follows:
3x + y = 11
-3x + 2y = 1 <-- imagine I put a huge addition sign to the very left of those equations.

Answer 2

What would you get when you do (-3x) + (3x)? X cancels out!
y + 2y = 3y
11 + 1 = 12
So now, what we are left with is this:

3y = 12
Solving for y,
y = 4.