if one of the zeroes of the cubic polynomial xraise to power 3 +ax raise to power 2+bx
+c is -1 then the product of other two zeroes is......
a. a-b-1
b. b-a-1
c. b-a+1
d. a-b+1 

Asked by Chanchal.sharma252 | 19th Jul, 2014, 11:09: AM

Expert Answer:

L e t space alpha comma beta space b e space t h e space o t h e r space z e r o e s space o f space t h e space c u b i c space p o l y n o m i a l comma space x cubed plus a x squared plus b x plus c equals 0 G i v e n space t h a t space minus 1 space i s space o n e space z e r o space o f space t h e space p o l y n o m i a l. T h u s comma space alpha cross times beta cross times open parentheses minus 1 close parentheses equals fraction numerator minus c over denominator 1 end fraction rightwards double arrow alpha beta equals c N o w space s u b s t i t u t e space open parentheses space minus 1 close parentheses cubed plus a open parentheses space minus 1 close parentheses squared plus b open parentheses space minus 1 close parentheses plus c equals 0 rightwards double arrow minus 1 plus a minus b plus c equals 0 rightwards double arrow c equals 1 minus a plus b rightwards double arrow alpha beta equals c equals 1 minus a plus b T h u s comma space left parenthesis c right parenthesis space i s space t h e space c o r r e c t space o p t i o n

Answered by Vimala Ramamurthy | 21st Jul, 2014, 09:14: AM

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