Answer:
1 year
Explanation:
8 + 7x = 2 + 13x 
Move the 2 to the other side by subtracting 2 from both sides.
6 + 7x = 13x 
Move the 7x to the other side by subtracting both sides by 7x. 
6 = 6x 
Divide both sides by 6. 
1 = x 
Therefore, x equals 1 and it will take 1 year for both trees to reach the same height.