Another equilibrium??? Show work please, thanks for the help?

Question

The equilibrium constant Kc for the reaction:
A(g) + B(g) yields C(g), is 0.76 at 150 degrees C. If 0.800 mol of A is added to 0.600 mol of Bin a 1.00 L container at 150 degrees C, what will be the equilibrium concentration of C?

ok im going to specify, serious answers only please, i have an exam coming up and need to understand this. thanks

Answer 1

Keq = [C]/[A][B]
[C] = Keq*[A]*[B]
[C] = 0.76*[0.8]*[0.6]
[C] = 0.36

Answer 2

Not a lot of people know this and in reality if I submit to you exactly how I come to the conclusions that I do and have, I would be forced to kill you. But what I can tell you is simply this:
a)
4x + 4y = -12
-2x + 3y = 14

Double the second equation and add:
4x + 4y = -12
-4x + 6y = 28
10y = 16
y = 16/10
y = 8/5

Then solve for x:
x + (8/5) = -3
x = -3 - 8/5
x = -4 3/5

b)
3x + 2y = 5
2x - 3y = 3

Multiply the top by 2 and the bottom by 3, then subtract:
6x + 4y = 10
6x - 9y = 9
13y = 1
y = 1/13

Then solve for x:
3x + 2(1/13) = 5
3x + 2/13 = 5
3x = 63/13
x = 21/13
x = 1 8/13

It appears I have won two points, yipeeee for me !!!