Question

A system of equations is shown below:

x + y = 3

2x – y = 6

The x-coordinate of the solution to this system of equations is _____.

Answer 1

To solve this problem you must apply the procceddure shown below:

1. You have the following system of equations:

x+y = 3
2x–y = 6

2. Then, you must clear the variable y from the first equation and susbtitute it into the second equation, as below:

x+y=3
y=3-x

2x-y=6
2x-(3-x)=6
2x-3+x=6
3x=6+3
3x=9

3. Therefore, the value of x is:

x=9/3
x=3

4. As you can see, the correct answer is:

x=9