What is the x-coordinate of the solution of the following system of equations?

3x + y = 6

x - y = 6

-3

0

3

The easiest way to solve this is by elimination.

3x - y = 6

6x + y = 21

Since you have a negative and positive y with the same coefficients (1), they cancel, and you add the other terms so it would look like:

9x = 27

Then solving for x leaves you with x = 3

Then you take the x value of three and plug it into to either of the equations, so

3 (3) - y = 6

9 - y = 6

subtracting 9

-y = - 3

then dividing by - 1

y = 3

so the solution is x = 3 y = 3 or (3,3)