Question

Question #dcc59

Answer 1

`b=-2`

Explanation:

According with the conditions we have

`a x^3 + b x^2 + 1=(x-r)(x^2-x-1)`

Equating the coefficients

`{(1 + r=0), (1 + r=0), (1 +b - r=0), (1 - a=0):}`

solving for `a,b,r` we obtain

`a=1,b=-2,r=-1`