Given that one of the zero of the cubic polynomial ax3+bx2+cx+d is zero ,then find the third zero.

Asked by  | 22nd Jun, 2013, 10:47: PM

Expert Answer:

There seems some mistake in the question you posted. However, if the question is correcr, then you can proceed the following way.
 
One zero = 0
Let the other two zeroes be P and Q.
Using the relations between zeroes and coefficients, we have:
P+Q=-b/a             (1)
PQ = c/a
 
Then,
(P-Q)2 = (P+Q)2 -4PQ = b2/a2 - 4c/a = b2-4ac/a2
From this relation, find P-Q. Denote this equation by (2).
Then solve the two equations (1) and (2) to get the value of P and Q.

Answered by  | 23rd Jun, 2013, 12:54: AM

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