Question

Find the values of a and b so that (x+1) and (x-1) are the factors of x^4+ax^3-3x^2+2x+b

Answer 1

put the value of x=-1
(-1)∧4+a(-1)∧3-3(-1)∧2+2(-1)+b=0
1-a-3-2+b=0
1-5-a+b=0
-4+b=a............eq1
now put the value of x=1
1∧4+a*1∧3-3*1∧2+2*1+b=0
4+a-3+2+b=0
5+a+b=0
a+b=-9
put the value of a in eq1
-4+b+b=-5
-4+2b=-5
2b=-5+4
b=-1/2

a=-4+b
  =-4+-1/2
  =-9


hope my ans helps you