If −4 is a zero of the polynomial x² − x − (2 + 2k), then the value of k is

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Question

This question was previously asked in

Bihar STET Paper I: Mathematics (Held In 2019 - Shift 1)

Answer 1

Concept use:

if a is the zero of the polynomial P(x) then P(a) = 0

Calculations:

−4 is a zero of the polynomial x2 − x − (2 + 2k) = P(x)

Hence, P(-4) = 0

4² - -4 - (2 + 2k) = 0

16 + 4 - (2 + 2k) = 0

20 = (2 + 2k)

20 - 2 = 2k

18 = 2k, k = 9

Hence, The Correct Answer is option 2.

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