Question

A person's systolic blood pressure, which is measured in millimeters of mercury (mm Hg), depends on a person's age, in years . The equation: P = 0.006y ^ 2 - 0.03y + 122

Answer 1

P = 0.006y² - 0.03y + 122

Part a:

For y = 47 years, we have:

$P=0.006\cdot47^2-0.03\cdot47+122=133.8\text{ mm Hg}$

Part B:

For P = 134.38 mm Hg, we have:

$\begin{gathered} 134.38=0.006y^2-0.03y+122 \\ 0.006y^2-0.03y-12.38=0 \\ y=\frac{-(-0.03)\pm\sqrt{(-0.03)^2-4\cdot0.006\cdot(-12.38)}}{2\cdot0.006} \\ y=\frac{0.03\pm\sqrt{0.29802}}{0.012} \end{gathered}$

Since only the positive root might be considered, we have:

y = 48 years (rounded)