10" tall
1) Gathering the data
2 weeks 5 weeks
18" tall 30" tall
2) Let's find the initial height of that sunflower since it is not a proportional growth we need to find it through a linear function.
(Since 30/5 = 6 and 18/2=9)
After finding the slope m, let's find the linear coefficient
y=mx +b
18 =2(4) +b
18= 8 +b
18-8=b
b=10
So the rule of that function is y=4x +10
3) Now we can find the initial height. Plugging x=0, where x is the number of weeks we have:
y = 4x +10
y=4(0) +10
y= 10
So the sunflower was 10" tall on the day it was planted.
