（x⁴+x²-4)(x⁴+x²+3)+10
=（x⁴+x²)²-(x⁴+x²)-12+10
=（x⁴+x²)²-(x⁴+x²)-2
=（x⁴+x²+1)(x⁴+x²-2)
=（x⁴+2x²+1-x²)(x²-1)(x²+2)
=[（x²+1)²-x²](x²+2)(x²-1)
=（x²+1+x)(x²+1-x)(x²+2)(x+1)(x-1)
=（x²+x+1)(x²-x+1)(x²+2)(x+1)(x-1)