Answer:
[tex]a=1[/tex]
[tex]b=-1[/tex]
Step-by-step explanation:
Once [tex](x-1)^2[/tex] is a factor and [tex](x-1)^2 = (x-1)(x-1)[/tex], we have that two roots of the cubic equation are equal to 1. So,
[tex]ax^3+bx^2+1 = (x-1)(x-1)(x-d)=0[/tex]
As [tex]d[/tex] the unknown root.
Expanding
[tex]ax^3+bx^2+1 = (x-1)(x-1)(x-d)=0[/tex]
[tex]ax^3+bx^2+1 = (x^2-2x+1)(x-d)=0[/tex]
[tex]ax^3+bx^2+1 = x^3-2x^2+x-dx^2+2dx-d=0[/tex]
Now, comparing the two expressions, we have
[tex]ax^3+bx^2+1 = x^3+(-2-d)x^2+(1+2d)x-d=0[/tex]
Therefore, know we know
[tex]a=1[/tex]
[tex]b=-2-d[/tex]
[tex]d=-1[/tex]
So,
[tex]b=-2-(-1)=-2+1=-1[/tex]
