Question 1071838: The sum of 2 numbers is 20, their product is 10. If the sum of their reciprocals is a, find a? Found 2 solutions by ankor@dixie-net.com, ikleyn:Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! he sum of 2 numbers is 20,
x + y = 20
y = -x+20
their product is 10.
xy = 10
replace y with (-x+20)
x(-x+20) = 10
a quadratic equation
-x^2 + 20x - 10 = 0
using the quadratic formula, two solutions
x = 19.487, then y = .513 (subtract x from 20)
x = .513, then y = 19.487
:
the sum of their reciprocals is a,
a = +
a = +
a = .0513 + 1.949
a = 2.00
You are given
x + y = 20, xy = 10.
You are asked about .
= = .
Now replace the numerator by 20, and replace the denominator by 2. You will get
= = = 2.
