To find the time in months \( t \) when the heights of Plant A and Plant B are equal, we will set their height equations equal to each other and solve for \( t \).
The equations for the heights are:
- Plant A: \( h = 4 + 2t \)
- Plant B: \( h = 8 + t \)
Setting the equations equal to each other:
\[ 4 + 2t = 8 + t \]
Now, we will solve for \( t \):
- Subtract \( t \) from both sides:
\[ 4 + 2t - t = 8 \]
This simplifies to:
\[ 4 + t = 8 \]
- Now, subtract 4 from both sides:
\[ t = 8 - 4 \]
This gives:
\[ t = 4 \]
Thus, the time in months when the heights of Plant A and Plant B are equal is \( t = 4 \).