If (x−1) is a factor of ax3−bx2+cx, what is the value of a3−b3+c3?
2abc
-2abc
3abc
-3abc
p(x)=ax3−bx2+cx Given (x−1) is a factor of p(x),
p(1)=a−b+c=0
It can be written as a+(−b)+c=0
We know that if a+b+c=0,a3+b3+c3=3abc
So, a3+(−b)3+c3=3a(−b)c=−3abc
If ax2+bx+c=0 and bx2+cx+a=0 have a common root
a ≠ 0, then a3+b3+c3abc=