Answer
It takes 2 years for the trees to be the same height
Work Step by Step
Tree 1: 3 + 1x
Tree 2: 4 + 1/2x
Next, we make the equations equal to each other:
$3 + 1x = 4 + 1/2x $
Subtract 1/2x and 3 from both sides;
$1/2x = 1$
Divide both sides by 1/2;
$x=2$