Q1 of 227 Page 82

Find the zeros of the following quadratic polynomials and verify the basic relationships between the zeros and the coefficients.

x2 – 15

Let f(x) = x2 – 15

Arranging equation in proper form.


Now, f(x) = x2 + 0x – 15


To find out zeros of the given polynomial.


We put f(x) = 0


x2 – 15 = 0


x2 = 0


So, (x + )(x – ) = 0


When, (x + ) = 0


Then, x = – .


When. (x – ) = 0


Then, x =


Our zeros are α = – and β = .


sum of zeros = α + β = – +


sum of zeros = α + β = 0


Product of zeros = αβ = – = – 15


Now, Comparing f(x) = x2 + 0x – 15 with standard equation ax2 + bx + c.


We get, a = 1, b = 0 and c = – 15.


We can verify,


Sum of zeros =


i.e. α + β =


α + β = 0


Product of zeros =


αβ =


Hence, relationship between zeros and coefficient is verified.


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