SOLUTION: The sum of a number and its reciprocal is 4. if it is known that the number is negative, find the number. Thank you in advance :)

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Question 799642: The sum of a number and its reciprocal is 4. if it is known that the number is negative, find the number. Thank you in advance :)
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
let the number be x
-x+ 1/(-x) = 4
multiply by -x
x^2+1=-4x
x^2+4x+1=0
a= 1 , b= 4 , c= 1

b^2-4ac= 16 + -4
b^2-4ac= 12
%09sqrt%28%0912%09%29=%093.46%09
x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=%28-b%2Bsqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=( -4 + 3.46 )/ 2
x1= -0.27
x2=%28-b-sqrt%28b%5E2-4ac%29%29%2F%282a%29
x2=( -4 -3.46 ) / 2
x2= -3.73