Help with a few problems

  • #1
i'm havin trouble with a few problems on my homework so help would be much appriciated

solve for x:

1) 3x^2 - 2x +1=0

2) x^2 -4x + 20 = 0

3) (-2/x+1) + (3/1-x) = 7/x^2-1

and
find p(-2) if P(x) = 2x^4 - x^3 + 4x^2 + -8x + 3

again thx for any help :)
 

Answers and Replies

  • #2
enigma
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Look up the quadratic formula for the first three.

For the last one, substitute -2 in everywhere you see x, multiply and add them together.

If you post an attempt, we can help you a bit more.
 
  • #3
i didnt think of using the quadratic formula i tried it but it still doesnt seem right i got
x=2/3 + or - i root60/6 for the 1st 1

and x = 6,-2 for the 2nd i must be doing something wrong
 
  • #4
enigma
Staff Emeritus
Science Advisor
Gold Member
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14
I've got complex answers for both of the first two as well, but they don't match your results. Probably missed a '-' sign somewhere.

For the third one, it looks like your parenthesis are a bit ambiguous.

(-2/x+1)

Is this (-2/x) +1 or -2/(x+1)?

Can you post your work, and we'll find the errors?
 

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