Question

if 5 is a zero of the quadratic polynomial x²- Kx - 15 then the value of k is
a) 2. b) -2. c)4. d) -4
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Answer 1

x^2-kx-15 =0

5^2-k5-15 =0 (given:x=5

25 -5k -15=0

10-5k=0

-5k=-10

k=-10/-5

k=2

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