Answer: 13
Step-by-step explanation:
If you remember the quadratic equation formula;

You can easily extract what is under the root to find the discriminant.

a = 3
b = 7
c = 3

The function modelled by the height (x) of the tree is as follows:
y - 180 = (368 - 180)/(7 - 3) (x - 3)
y - 180 = 47(x - 3) = 47x - 141
y = 47x - 141 + 180 = 47x + 39
Therefore, after 10 years, the tree will be 47(10) + 39 = 470 + 39 = 509 cm tall
Y=(1/5)^x would be the only equation demonstrating decay of these