Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Quadratic equation problem

  1. Jan 9, 2009 #1
    1. Consider the quadratic equation ax^2+px+aq+q=0 where a does not equal to zero & p and q are constants . It is known that one of the roots of the quadratic equation is always 1 regardless of the value of a. Prove that p+q=0

    3. I have tried to factorize it and it became x(ax+p)+q(a+1)=0 but thats it. I kinda stuck /b]
  2. jcsd
  3. Jan 9, 2009 #2
    Hi Requal,
    That 1 is a root of the quadratic equation ax^2 + px + aq + q = 0 means that x=1 satisfies the equation; so plugging in x=1 we have a + p + aq + q = 0.
    We are told this is true for any (nonzero) value of a. Can you take it from here?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook