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

1.	If (x+k) is a factor of the polynomial x^2-2x-15 and x^3 + a . Find k and a . Class 10
Answer» Step-by-step EXPLANATION: OPEN in ANSWR app 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_______________

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

Answer»

Step-by-step EXPLANATION:

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_______________