Business calcules math

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+118P=0.006y2-0.03y+118

gives a person's blood pressure, PP, at age y years.

A.) Find the systolic pressure, to the nearest tenth of a millimeter, for a person of age 50 years.

B.) If a person's systolic pressure is 126.4 mm Hg, what is their age (rounded to the nearest whole year)?

Answer 1

P(y) = 0.006y^2 - 0.03y + 118

P(50)= .006(50)^2 - .03(50) + 118

= .006(2500) - .1.5 +118

= 15 + 116.5

= 131.5

126.4 = .006y^2 -.03y + 118

.006y^2 - .03y - 8.4 = 0

use the quadratic formula

y = .03/.012 +/- (1/.012)sqr(.03^2 + .024(8.4))

=2.5 + or - sqr(.0009 + .2016)/.012

= 2.5 + or - sqr(.2025)/.012=2.5 + or - 37.5 years old

= 40 years old