Answer:
Plant F;
Plant G;
Plant G
Step-by-step explanation:
Given that:
Plant F :
 f(t)=0.5x+2 
From the growth graph given for the second plant ; plant G
Point 1 (0, 5) ; point 2(16, 9)
Slope = Rise / Run = (9 - 5) / (16 - 0) = 4 / 16 = 0.25
Intercept = 5 ( point where fitted line crosses the y-axis)
Linear slope intercept relation : y = mx + c
m = slope ; c = intercept
g(x) = 0.25x + 5
The slope value of plant F = 0.5
Slope value of plant G = 0.25
F > G
Hence, F is growing at a faster rate
The starting height is given by the intercept value of the two equations ;
Plant F, intercept = 2
Plant G, intercept = 5
G > F 
Hence, G was taller, to begin with 
Height after 8 days :
x = 8
f(8)=0.5(8)+2 
f(8) =  4 +2 = 6 
g(8) = 0.25(8) + 5 
g(8) =  2 + 5 = 7
Hence, G was taller after 8 days