We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website. cookie policy and privacy policy.
 
+0  
 
0
121
1
avatar

Suppose the decimal 0.28 is equal to {1}{n}+{2}{n^2}, where n is negative. Find  n.

 May 5, 2019
 #1
avatar+104933 
+1

1(n) + 2(n^2)   =  0.28

 

2n^2  + n  - 0.28  = 0      [ multiply through by 100 ]

 

200n^2 + 100n - 28  = 0

 

50n^2 + 25n - 7   = 0

 

(5n - 1)(10n + 7)  = 0

 

Only the second factor will produce a negative n

 

10n + 7  = 0

 

10n  = -7

 

n  = -7/10

 

 

 

cool cool cool

 May 5, 2019

32 Online Users