Question

If (x+k) is a factor of the polynomial x^2-2x-15 and x^3 + a . Find k and a . Class 10

Answer 1

Step-by-step explanation:

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x7(k+2).(x+k))x2−2x−15x2+kx________________________(−k−2)x−15−(k+2)x−k(k+2)___________________________k(k+2)−15

(x+k) is a factor of x2−2x−15 and x2+a

⇒k(k+2)−15=0

⇒k2+2k−15=0

⇒k2+5k−3k−15=0

⇒k(k+5)−3(k+5)=0

⇒k=3or−5

if k=3

x−3(x+3))x2+a  x2+3x_______________

Answer 2

Answer:

(x+k) is the factor of polynomial x²-2x-15

therefore,

X=-K

put the value of x

x²-2X-15=0

(-K)²-2 (-K)-15=0

K²+2k-15=0

K²+5K-3K-15=0

K (K+5)-3(K+5)=0

(K-3) (K+5)=0

K=3 or K=-5

we take K=3

therefore,

(x+k )=0

x+3=0

x=-3

again,

X³+ a=0

(-3)³+ a=0

-27 + a=0

a=27

HOPE THIS WILL HELP YOU