Answer:
12 weeks
Explanation:
Step one:
given data
let the heights of the plants be y
and the number of weeks be x
Plant A
y=3x+8.5--------------1
Plant B
y=2.5x+14.5----------2
Required
The number of weeks taken for both plants to have the same height
,equate the two expressions above
3x+8.5=2.5x+14.5
3x-2.5x=14.5-8.5
0.5x= 6
divide both sides by 0.5
x= 6/0.5
x= 12 weeks