Answer:

Explanation:
Please find the attachment. 
Let d represent the distance that takes him directly back home.
We have been given that Reynaldo rode his bike 2 miles north and 3 miles east. 
Upon looking at our attachment we can see that distance covered by Reynaldo forms a right triangle, where d is the hypotenuse.
To solve for d we will use Pythagoras theorem.
 , where,
, where,
a and b = Legs of right triangle,
c = Hypotenuse of triangle.
Upon substituting our given values in above equation we will get,

Therefore, the equation 
 represents the distance, d, that takes Reynaldo directly back home.
 represents the distance, d, that takes Reynaldo directly back home.