Answer:
We can use either elimination or substitution to solve this problem. Here's one way to solve it using substitution:
Step 1: Let's call the current age of your dog "x" and the current age of your friend "y".
Step 2: We know that your dog is 6 years younger than your friend, so we can write the equation:
x = y - 6
Step 3: We also know that in 3 years, your friend will be twice as old as your dog, so we can write the equation:
y + 3 = 2(x + 3)
Step 4: Now we can substitute the first equation into the second equation.
y + 3 = 2(x + 3)
(y - 6) + 3 = 2(x + 3)
x + 3 = 2(x + 3)
Step 5: Now we can solve the equation for x:
x + 3 = 2x + 6
3 = x
So the current age of your dog is 3 years old.