Question

.If two zeroes of x³ + x² -5x -5 are √5 and -√5, then its third zero is

Answer 1

Question :

If two zeroes of x³ + x² -5x - 5 are √5 and -√5, then its third zero is

Answer :

third zero = -1

Step-by-step explanation :

 Given :

  two zeroes of x³ + x² -5x -5 are √5 and -√5

  To find :

  third zero

  Solution :

 

    Let third zero be "a"

One of the relationships between the zeroes and coefficients of cubic polynomial is as follows :

    Sum of zeroes = -x² coefficient/x³ coefficient

   √5 + (-√5) + a = -1/1

    √5 - √5 + a = -1

        0 + a = -1

           a = -1

=> Third zero = -1