If one of the zeroes of the quadratic polynomial (k-1) x² + k x + 1 is -3, then the value of k is
a. 4/3
b. -4/3
c. 2/3
d. -2/3
Solution:
Given, the quadratic polynomial is (k-1) x² + k x + 1.
One zero of the polynomial is -3.
We have to find the value of k.
Let f(x) = (k-1) x² + k x + 1
f(-3) = 0
Put x = -3 in the given polynomial
(k-1) (-3)² + k (-3) + 1 = 0
(k-1)(9) - 3k + 1 = 0
9k - 9 - 3k + 1 = 0
By grouping,
9k - 3k - 9 + 1 = 0
6k - 8 = 0
6k = 8
k = 8/6
k = 4/3
Therefore, the value of k is 4/3.
✦ Try This: If one of the zeroes of the quadratic polynomial (k-1) x² + k x + 1 is 2, then the value of k is
Given, the quadratic polynomial is (k-1) x² + k x + 1.
One zero of the polynomial is 2.
We have to find the value of k.
Let f(x) = (k-1) x² + k x + 1
f(2) = 0
Put x = -3 in the given polynomial
(k-1) (2)² + k (2) + 1 = 0
(k-1)(4) + 2k + 1 = 0
4k - 4 + 2k + 1 = 0
By grouping,
4k + 2k - 4 + 1 = 0
6k - 3 = 0
6k = 3
k = 3/6
k = 1/2
Therefore, the value of k is 1/2.
☛ Also Check: NCERT Solutions for Class 10 Maths Chapter 2
NCERT Exemplar Class 10 Maths Exercise 2.1 Problem 1
If one of the zeroes of the quadratic polynomial (k-1) x² + k x + 1 is -3, then the value of k is a. 4/3, b. -4/3, c. ⅔, d. -2/3
Summary:
If one of the zeroes of the quadratic polynomial (k-1) x² + k x + 1 is -3, then the value of k is 4/3
☛ Related Questions:
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