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 2 years ago
You are given that f(x) = x^3  19x + 30
1.) Calculate f(0) and f(3). Hence write down a factor of f(x).
Thanks.
 2 years ago
You are given that f(x) = x^3  19x + 30 1.) Calculate f(0) and f(3). Hence write down a factor of f(x). Thanks.

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mukushla
 2 years ago
Best ResponseYou've already chosen the best response.1can u evaluate f(0) and f(3) ?

headge
 2 years ago
Best ResponseYou've already chosen the best response.1What does evaluate mean?

headge
 2 years ago
Best ResponseYou've already chosen the best response.1Hmmm hang on. Do you mean put them into the f(X)= thing?

Hero
 2 years ago
Best ResponseYou've already chosen the best response.0Evaluate means to do this: f(x) = x^3  19x + 30 f(0) = (0)^3  19(0) + 30 = ? f(3) = (3)^3  19(3) + 30 = ?

headge
 2 years ago
Best ResponseYou've already chosen the best response.1Yes ok Ill have a go at that and tell you what I got thanks.

headge
 2 years ago
Best ResponseYou've already chosen the best response.1Right for f(0) I got 30 and the next one 0

headge
 2 years ago
Best ResponseYou've already chosen the best response.1Did it again and got 0 again.

Hero
 2 years ago
Best ResponseYou've already chosen the best response.0f(3) = (3)^3  19(3) + 30 = 27  57 + 30 = 30 + 27  57 = 57  57 = 0 OK

headge
 2 years ago
Best ResponseYou've already chosen the best response.1Yes!! So now I have two more questions. Are you up for helping?

headge
 2 years ago
Best ResponseYou've already chosen the best response.1Wait what is the 'hence write down the factor of f(x)' bit?

Hero
 2 years ago
Best ResponseYou've already chosen the best response.0If you calculated f(3) = 0, then (x3) is a factor

headge
 2 years ago
Best ResponseYou've already chosen the best response.1:) I remeber that now. The 0 ones it is.

headge
 2 years ago
Best ResponseYou've already chosen the best response.1(ii) Find p and q such that f(x) = (x2)(x^2 + px +q). How does one go about this?

headge
 2 years ago
Best ResponseYou've already chosen the best response.1@karatechopper @myininaya

Coolsector
 2 years ago
Best ResponseYou've already chosen the best response.0(x2)(x^2 + px +q) = x^3 +px^2 +qx 2x^2 2px 2q = x^3 +(p2)x^2 +(q2p)x  2q and the orig is x^3  19x + 30 so we know that p2 should be 0 and q2p should be 19 and 2q should be 30 can you answer now ?

headge
 2 years ago
Best ResponseYou've already chosen the best response.1Wait....Where has that big line came from? ohhh you timesed out the brackets! Ok wait a min.

headge
 2 years ago
Best ResponseYou've already chosen the best response.1I get it up to when you start saying the so we know p2=0 bit. I dont know how we know that.

Coolsector
 2 years ago
Best ResponseYou've already chosen the best response.0ok you see we have a term (p2)x^2 but in the general equation we dont have x^2 at all .. so we have to make it disappear .. we do this by saying p2 = 0
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