Question 1:
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients.
Answer:
The value of is zero when x − 4 = 0 or x + 2 = 0, i.e., when x = 4 or x = −2
Therefore, the zeroes of are 4 and −2.
Sum of zeroes =
Product of zeroes
The value of 4s2 − 4s + 1 is zero when 2s − 1 = 0, i.e.,
Therefore, the zeroes of 4s2 − 4s + 1 are and .
Sum of zeroes =
Product of zeroes
The value of 6x2 − 3 − 7x is zero when 3x + 1 = 0 or 2x − 3 = 0, i.e., or
Therefore, the zeroes of 6x2 − 3 − 7x are .
Sum of zeroes =
Product of zeroes =
The value of 4u2 + 8u is zero when 4u = 0 or u + 2 = 0, i.e., u = 0 or u = −2
Therefore, the zeroes of 4u2 + 8u are 0 and −2.
Sum of zeroes =
Product of zeroes =
The value of t2 − 15 is zero when or , i.e., when
Therefore, the zeroes of t2 − 15 are and .
Sum of zeroes =
Product of zeroes =
The value of 3x2 − x − 4 is zero when 3x − 4 = 0 or x + 1 = 0, i.e., when or x = −1
Therefore, the zeroes of 3x2 − x − 4 are and −1.
Sum of zeroes =
Product of zeroes
Question 2:
Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively.
Answer:
Let the polynomial be , and its zeroes be and .
Therefore, the quadratic polynomial is 4x2 − x − 4.
Let the polynomial be , and its zeroes be and .
Therefore, the quadratic polynomial is 3x2 − x + 1.
Let the polynomial be , and its zeroes be and .
Therefore, the quadratic polynomial is .
Let the polynomial be , and its zeroes be and .
Therefore, the quadratic polynomial is .
Let the polynomial be , and its zeroes be and .
Therefore, the quadratic polynomial is .
Let the polynomial be .
Therefore, the quadratic polynomial is .