Question

x-2 is a factor of x3 + ax2 + 6 x- b and a- b is equal to 7 then find the values of a and b​

Answer 1

Answer:

Let p(x) = x3 + ax2 + bx +6

(x-2) is a factor of the polynomial x3 + ax2 + b x +6

p(2) = 0

p(2) = 23 + a.22 + b.2 +6 =8+4a+2b+6 =14+ 4a+ 2b = 0

7 +2 a +b = 0

b = - 7 -2a -(i)

x3 + ax2 + bx +6 when divided by (x-3) leaves remainder 3.

p(3) = 3

p(3) = 33 + a.32 + b.3 +6= 27+9a +3b +6 =33+9a+3b = 3

11+3a +b =1 => 3a+b =-10 => b= -10-3a -(ii)

Equating the value of b from (ii) and (i) , we have

(- 7 -2a) = (-10 - 3a)

a = -3

Substituting a = -3 in (i), we get

b = - 7 -2(-3) = -7 + 6 = -1

Thus the values of a and b are -3 and -1 respectively.

❤Hope this helps you ARMY•••✨

Answer 2

Answer:

if it is helpful like this answer

Explanation:

f(x)=x  

3

+ax  

2

+bx+6

(x−2) in a factor ⇒f(2)=0

f(2)⇒2  

3

+a(2)  

2

+2b+6=0

⇒8+4a+2b+b=0

⇒4a+2b+14=0

⇒2a+b+7=0 -(1)

f(x−3)=3 (Remainder)

⇒f(3)⇒3  

3

+a(3)  

2

+b×3+6=3

⇒27+9a+3b+b=3

⇒9a+3b+30=0

⇒3a+b+10=0 _____ (2)

From (1) & (2)

b=−2a−7 & b=−10−3a

−2a−7=−10−3a

3a−2a=−10+7

a=−3

from (3)

b=−2(a)−7=2(−3)−7

  =6−7

b=−1