1. **State the problem.**
We are given the system of equations:
$$2x+y=8$$
$$2x-y=12$$
We need to find $x$ and $y$.
2. **Use the elimination method.**
A good formula idea for systems is to add or subtract equations so one variable cancels out.
Here, the $y$ terms are $+y$ and $-y$, so adding the equations will eliminate $y$.
3. **Add the equations.**
$$
\begin{aligned}
2x+y&=8\\
2x-y&=12\\
\hline
4x+\cancel{y-y}&=20
\end{aligned}
$$
So we get:
$$4x=20$$
4. **Solve for $x$.**
Divide both sides by $4$:
$$\frac{4x}{4}=\frac{20}{4}$$
With cancellation shown:
$$\frac{\cancel{4}x}{\cancel{4}}=\frac{20}{4}$$
So:
$$x=5$$
5. **Substitute $x=5$ into one equation to find $y$.**
Use $2x+y=8$:
$$2(5)+y=8$$
$$10+y=8$$
Subtract $10$ from both sides:
$$y=8-10$$
$$y=-2$$
6. **Check the solution.**
Plug $x=5$ and $y=-2$ into the second equation:
$$2(5)-(-2)=10+2=12$$
That matches, so the solution is correct.
7. **Final answer.**
$$x=5,\quad y=-2$$
Linear System 785798
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