Answer:
The man would be 40 years old.
Step-by-step explanation:
Blood pressure as function of age:
Is given by the following equation:
![P = 0.006A^2 - 0.02A + 120](https://tex.z-dn.net/?f=P%20%3D%200.006A%5E2%20-%200.02A%20%2B%20120)
Find the age of a man whose normal blood pressure measures 129 mmHg.
This is A for which P = 129. So
![129 = 0.006A^2 - 0.02A + 120](https://tex.z-dn.net/?f=129%20%3D%200.006A%5E2%20-%200.02A%20%2B%20120)
![0.006A^2 - 0.02A - 9 = 0](https://tex.z-dn.net/?f=0.006A%5E2%20-%200.02A%20-%209%20%3D%200)
Solving a quadratic equation:
Given a second order polynomial expressed by the following equation:
.
This polynomial has roots
such that
, given by the following formulas:
In this question:
Quadratic equation with
. So
Age has to be a positive number, so rounding to the nearest year:
The man would be 40 years old.