Q5 of 30 Page 36

If one zero of the polynomial 3x2 – 8x + 2k + 1 is seven times of other then, Find the value of k.

The polynomial 3x2 – 8x + 2k + 1 is quadratic hence it will have two zeroes


Let one zero of polynomial be α


As the other one is 7 times hence it would be 7α


Thus, α and 7α are roots of 3x2 – 8x + 2k + 1


Compare 3x2 – 8x + 2k + 1 with ax2 + bx + c = 0


a = 3, b = –8 and c = 2k + 1


the sum of roots of quadratic =



Substituting values of b and a




The product of roots of quadratic =



Substituting values of c and a



Substituting the value of









Hence the value of


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