Question

Find the value of a and b so that x + 1 and x -1 are factors of x4 + ax3 - 3x2 + 2x +b.

Answer 1

Answer:

a= -2 and b = 2

do thank you, rate 5 star and comment

Step-by-step explanation:

p(x)=x^4+ax^3-3x^2+2x+b

let x= -1

p( -1) = ( -1)^4 + a( -1)^3 - 3( -1)^2 + 2( -1) + b

0 = 1 - a - 3 - 2 + b

0 = -4 - a + b

a = b-4-----(1)

now,

let x = 1

p(1) = (1)^4 + a(1)^3 - 3(1)^2 + 2(1) + b

0 = 1+a-3+2+b

0 = a+b------(2)

Now,

put value of a in eq(2)

0 = b-4+b

4 = 2b

b = 2

Now,

put value of b in eq(1)

a= 2-4

a= -2