P = 0.006 A^2 - 0.02 A + 120
Where:
P = blood pressure
A = age
Replace P by 123 and solve for A
123 = 0.006 A^2 - 0.02 A + 120
0 = 0.006 A^2 - 0.02 A + 120 -123
0= 0.006 A^2 - 0.02 A - 3
The equation is in the form:
Ax^2+ b x + c
Where:
a = 0.006
b= -0.02
C= -3
Apply the quadratic formula:
[tex]\frac{-b\pm\sqrt[]{b^2-4\cdot a\cdot c}}{2\cdot a}[/tex]
Replace:
[tex]\frac{-(-0.02)\pm\sqrt[]{(-0.02)^2-4\cdot0.006\cdot-3}}{2\cdot0.006}[/tex][tex]\frac{0.02\pm\sqrt[]{0.0004+0.072}}{0.012}[/tex][tex]\frac{0.02\pm0.26907248}{0.012}[/tex]
Positive:
(0.02+0.26907248) /0.012 = 24.1 years
Negative:
(0.02-0.026907248) /0.012 = -0.57
Since age can't be negative the answer is 24.1 years old
