(-2x-1)²-4(x-1)(x+2),怎么算?

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(-2x-1)²-4(x-1)(x+2),怎么算?

原式=(2x+1)²-4(x²+x-2)
=4x²+4x+1-4x²-4x+8
=9

=4x²+4x+1-4(x²+x-2)
=4x²+4x+1-4x²-4x+8
=9