For the bottom question, we know each plant’s height in terms of e and they are:

> (2e - 3)
> (4e + 1)
> (e + 2)

So, to find out the total height of all 3, you need to add all of them up:

(2e - 3) + (4e + 1) + (e + 2)
= 2e + 4e + e - 3 + 1 + 2
= 7e

A) total height of plants = 7e

To find out the height of the tallest plant, you’d need to find out what e is.

Since they told you average height of 3 plants is 35cm, so you know the total height of all 3 plants = 35cm x 3 = 105cm.

From part (A),
total height of all plants
= 7 e which is also 105cm.

7e = 105cm
So e = 15cm

So now, you can find out the height of each plant:

> (2e - 3) = 30 - 3 = 27
> (4e + 1) = 60 + 1 = 61
> (e + 2) = 15 + 2 = 17

B) So tallest plant is 61cm.