✨ Best Answer ✨
①
x⁸-y⁸
=(x⁴)²-(y⁴)²
=(x⁴+y⁴)(x⁴-y⁴)
=(x⁴+y⁴)((x²)²-(y²)²)
=(x⁴+y⁴)(x²+y²)(x²-y²)
=(x⁴+y⁴)(x²+y²)(x+y)(x-y)
②
x³+x²-x-1
=x²(x+1)-(x+1)
=(x+1)(x²-1)
=(x+1)(x+1)(x-1)
=(x+1)²(x-1)
③
x²-y²+2y-1
=x²-(y²-2y+1)
=x²-(y-1)²
=(x+y-1)(x-y+1)