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Homework Statement
If (x-3) is a factor of: x^2 - 4x + c, what is c?
Homework Equations
The Attempt at a Solution
I am really stuck here. When presented with these types of questions, what is the FIRST thing you look at/do ?
Thanks so much.
There's a theorem that deals with this. If x - a is a factor of a polynomial f(x), then f(a) = 0.Homework Statement
If (x-3) is a factor of: x^2 - 4x + c, what is c?
Homework Equations
The Attempt at a Solution
I am really stuck here. When presented with these types of questions, what is the FIRST thing you look at/do ?
Thanks so much.
The first thing I ask, is what do you know about polynomials and factoring.Homework Statement
If (x-3) is a factor of: x^2 - 4x + c, what is c?
Homework Equations
The Attempt at a Solution
I am really stuck here. When presented with these types of questions, what is the FIRST thing you look at/do ?
Thanks so much.
Do you really have to ask that? Is x-3 a factor of ##x^2-4x+7##? If it is you are done, otherwise you might want to check your arithmetic.Holy crap, think I got it. Please let me know if correct?
If (x-3) is a factor of: x^2 - 4x + c, what is c?
(3)^2 - 4(3) + c
9 - 16 + c = 0
c = 7
? is that correct????
What is 4(3) ?Holy crap, think I got it. Please let me know if correct?
If (x-3) is a factor of: x^2 - 4x + c, what is c?
(3)^2 - 4(3) + c
9 - 16 + c = 0
c = 7
? is that correct????
Work some examples out for yourself.So correct answer is:
c = +3
Umm... sorry if this is a dumb question, but the last 2 I did, C is always the same as what they are telling is a factor of.
So, this one I just did, they say (x+3) is a factor of..... would c automatically be +3?
The answer turned out to be +3.
Can someone give me another similar example to try???
Yes.Hi sammy.
Ok, so for the question you gave me: If (x+3) is a factor of: x^{2} - 4x + c, what is c?
c would = -21 ?
Nukeman, I will suggest again, when you have a problem like that and you think c = -21 so your function is ##x^2-4x-21##, why don't you just try factoring it yourself and see if x+3 is a factor instead of asking us if -21 is correct?Hi sammy.
Ok, so for the question you gave me: If (x+3) is a factor of: x2 - 4x + c, what is c?
c would = -21 ?