计算 (x+2)²-(x-1)(x+2) (m-2n+3)(m+2n-3)

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计算 (x+2)²-(x-1)(x+2) (m-2n+3)(m+2n-3)
计算 (x+2)²-(x-1)(x+2) (m-2n+3)(m+2n-3)

计算 (x+2)²-(x-1)(x+2) (m-2n+3)(m+2n-3)
(x+2)²-(x-1)(x+2)
=x^2+4x+4-(x^2+x-2)
=3x+6
(m-2n+3)(m+2n-3)
=m^2-(2n-3)^2
=m^2-4n^2-9+12n