7(m^3-m-1)-3(m^3+m)
=7m³-7m-7-3m³-3m
=4m³-10m-7
2x^5(-x)^2-(-x^2)^3(-7x)
=2X^7-(-X^6)(-7X)
=2X^7-7X^7
=-5 X^7
(x+1)(x-1)(x^2+1)
=(X²-1)(X²+1)
=X^4 - 1
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