As given by the question
There are given that the equation
[tex]H(x)=0.20x+14.25[/tex]Now,
From the equation, H is the height of the plant and x is the months.
Then,
The plants height after 20 months,
Put x =20 into the given equation
So,
[tex]\begin{gathered} H(x)=0.20x+14.25 \\ H(x)=0.20\times20+14.25 \\ H(x)=4+14.25 \\ H(x)=18.25 \end{gathered}[/tex]Hence, the plants height after 20 months is 18.25 meters.