Question 1103439
Let x = "one number"
then x+3 is the other number
—
x+(x+3) = 7   
Combine like-terms:
2x + 3 = 7
Subtract 3 from both sides:
2x = 4
Divide both sides by 2:
x = 2    ( —>  x+3 = 5 )
—
Ans:  The numbers are 2 and 5
—
Check:  
 5 = 2+3  (ok)
 5+2 = 7  (ok)