Respuesta :

Answer:

r=3

Step-by-step explanation:

[tex]\frac{3-(-1)}{r+5} =\frac{1}{2} \\\frac{4}{r+5} =\frac{1}{2} \\\frac{4}{8}=\frac{1}{2} \\r+5=8\\-5\\r=3\\[/tex]