1. Select the suitable option:
I. The value of k for which -1/2 is zero of polynomial f (x) = x squared space plus space 2 k x minus 3
a)  11/4
b) -11/4
c) 4/11
d) -1/3
 
II. If one of the zeroes of cubic polynomial x cubed plus a x squared plus b x plus c is 2, then the product of other two zeroes is:
a) c/2
b)-2/c
c)-c/2
d)2/c
 

Asked by Ŝũmiť Ğőyãĺ | 4th Jul, 2014, 04:11: PM

Expert Answer:

For the polynomial f(x)= x2 + 2kx - 3, it is given that fraction numerator minus 1 over denominator 2 end fraction is a zero of the given polynomial.

rightwards double arrow f left parenthesis fraction numerator minus 1 over denominator 2 end fraction right parenthesis space equals space 0 rightwards double arrow space open parentheses fraction numerator minus 1 over denominator 2 end fraction close parentheses squared plus space 2 k left parenthesis fraction numerator minus 1 over denominator 2 end fraction right parenthesis minus 3 space equals space 0 rightwards double arrow space 1 fourth space minus space k space minus space 3 space equals space 0 rightwards double arrow space 1 fourth space minus space 3 space equals space k rightwards double arrow space fraction numerator 1 space minus space 12 over denominator 4 end fraction space equals space k rightwards double arrow space k space equals space fraction numerator minus 11 over denominator 4 end fraction

Hence option (b) is correct.

Answered by Mili Hariyani | 6th Jul, 2014, 09:17: AM

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