+0  
 
0
964
4
avatar+262 

theres is something i cant understamd

 

2x2-3x+1>0

when i use the quadratic formula i get the answer that the root  is at x=1/2 ,1

but when i'm solving it by using the trinom i get a different answer :te root at x=-1,-2

 Sep 8, 2015

Best Answer 

 #3
avatar+33657 
+5

\(2x^2-3x+1\rightarrow(2x-1)(x-1)\)

 

This equals zero when x = 1/2 and x = 1  so 2x2 - 3x + 1 is greater than zero when x is less than 1/2 and greater than 1.

 

 quadratic

 Sep 8, 2015
edited by Alan  Sep 8, 2015
 #3
avatar+33657 
+5
Best Answer

\(2x^2-3x+1\rightarrow(2x-1)(x-1)\)

 

This equals zero when x = 1/2 and x = 1  so 2x2 - 3x + 1 is greater than zero when x is less than 1/2 and greater than 1.

 

 quadratic

Alan Sep 8, 2015
edited by Alan  Sep 8, 2015
 #4
avatar+129849 
+5

2x2-3x+1>0      factor   and set to 0

 

(2x -1)(x - 1)  =  0       setting each factor to 0, we get that x = 1/2 and x = 1

 

Then, the solution(s)   lie  in one or more of these intervals :

 

( - infinity, 1/2), (1/2, 1) , (1, infinity )

 

Norrmally, if the middle interval solves the problem, the ourside two won't, or vice-versa

 

Let's test  point in the middle interval to see if it satisfies the original equation - I'll pick 3/4.....so we have

 

2(3/4)2 -3(3/4) + 1 > 0

 

-1/8 > 0     and this is false.......so the other two intervals are the ones that solve the problem.......see the graph, here:  https://www.desmos.com/calculator/763e2oupae

 

 

 

cool cool cool

 Sep 8, 2015

1 Online Users