Answer:
The answer is D)
Step-by-step explanation:
hope it helps
[tex]\boxed{\text{\sf \Large D}}[/tex]
Add both equations
[tex](x+x)+(y-y)=2^m+2^n[/tex]
[tex]2x=2^m+2^n[/tex]
Divide both sides by 2
[tex]\large \text{$ x=\frac{2^m+2^n}{2} $}[/tex]