Answer:
x²+x+1
Step-by-step explanation:
1st one,
x³-1
= (x-1)(x²+x+1)
2nd one,
x⁴+x²+1
= x⁴+x³-x³+x²+x²-x²+1+x-x
= x⁴+x³+x²-x³-x²-x+x+x²+1
= x²(x²+x+1)-x(x²+x+1)+(x²+x+1)
= (x²+x+1)(x²-x+1)
3rd one,
x³+1+2x²+2x
= x³+x²+x²+x+x+1
= x³+x²+x+x²+x+1
= x(x²+x+1)+(x²+x+1)
= (x²+x+1)(x+1)
So, here the common part among these three is,
x²+x+1, so it's the H.C.F.
