Explanation
We are given the following equations:
[tex]\begin{gathered} x+y=9\text{ \lparen equation 1\rparen} \\ x-y=3\text{ \lparen equation 2\rparen} \end{gathered}[/tex]We are required to determine the value of x.
We can achieve this by using the elimination method as follows:
[tex]\begin{gathered} Equation\text{ 1 + Equation 2} \\ x+x+y+(-y)=9+3 \\ 2x+0=12 \\ 2x=12 \\ \frac{2x}{2}=\frac{12}{2} \\ x=6 \end{gathered}[/tex]Hence, the value of x is:
[tex]x=6[/tex]