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    The equation f(x) =0 has a repeated root, where f(x)=4x^2+px+q . When f (x) is divided by (x +1) the remainder is 1. Find the values of p and q.
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    (Original post by heatabi11)
    The equation f(x) =0 has a repeated root, where f(x)=4x^2+px+q . When f (x) is divided by (x +1) the remainder is 1. Find the values of p and q.
    If it has a repeated root then f(x) can be written in the form  (2x+a)^2 , and you know that  f(-1)=1 . Solve the simultaneous equations to find p and q.
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    (Original post by Zacken)
    Blah blah, what's your attempt? What thoughts do you have? This isn't a do-my-homework-for-me site.
    my attempt got me to x=-1

    then substituting that in got 3+q=p

    was unsure how to go from there to get two sets of answers and add in the whole repeated root business
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    (Original post by heatabi11)
    my attempt got me to x=-1

    then substituting that in got 3+q=p

    was unsure how to go from there to get two sets of answers and add in the whole repeated root business
    Great progess! It'd have been so useful for you to have included that in the OP. Oh well, now you know for next time!

    You've got one equation in q and p, so you should be aiming to get another so you can solve simultaneously.

    What can you say about the discriminant of the quadratic if they have equal roots?
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    (Original post by Zacken)
    Blah blah, what's your attempt? What thoughts do you have? This isn't a do-my-homework-for-me site.
    Triggered. :awesome:
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    (Original post by Zacken)
    Great progess! It'd have been so useful for you to have included that in the OP. Oh well, now you know for next time!

    You've got one equation in q and p, so you should be aiming to get another so you can solve simultaneously.

    What can you say about the discriminant of the quadratic if they have equal roots?
    woah didnt think of the discriminant what a spaz... the discriminant must be 0 yes?
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    (Original post by heatabi11)
    woah didnt think of the discriminant what a spaz... the discriminant must be 0 yes?
    Correct.

    so p-4q=0 ??
    Not so correct: discriminant is b^2 - 4ac = 0.
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    (Original post by Zacken)
    Correct.



    Not so correct: discriminant is b^2 - 4ac = 0.
    ya i deleted that so p^2-16q=0
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    (Original post by heatabi11)
    ya i deleted that so p^2-16q=0
    Yes. Now sub in p = 3+q and solve.
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    (Original post by Zacken)
    Yes. Now sub in p = 3+q and solve.
    woah thanks man you literally saved me
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    (Original post by heatabi11)
    woah thanks man you literally saved me
    You're welcome, just make sure to provide your own thoughts/attempts in the OP in the future, thanks.
 
 
 
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