(2m+n)(2m-n)-3(2m-n)的2次方+(-3n-4m)(4m-3n),求化简.

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(2m+n)(2m-n)-3(2m-n)的2次方+(-3n-4m)(4m-3n),求化简.(2m+n)(2m-n)-3(2m-n)的2次方+(-3n-4m)(4m-3n),求化简.(2m+n)(2m-

(2m+n)(2m-n)-3(2m-n)的2次方+(-3n-4m)(4m-3n),求化简.
(2m+n)(2m-n)-3(2m-n)的2次方+(-3n-4m)(4m-3n),求化简.

(2m+n)(2m-n)-3(2m-n)的2次方+(-3n-4m)(4m-3n),求化简.
(2m+n)(2m-n)-3(2m-n)的2次方+(-3n-4m)(4m-3n)
=4m²-n²-3(4m²-4mn+n²)+(9n²-16m²)
=4m²-n²-12m²+12mn-3n²+9n²-16m²
=-24m²+12mn+5n²

解(2m+n)(2m-n)-3(2m-n)²+(-3n-4m)(4m-3n)
=(2m-n)[2m+n-3(2m-n)]-(3n+4m)(4m-3n)
=(2m-n)[-4m+4n]-(3n+4m)(4m-3n)
=-(2m-n)[4m-4n]-(4m+3n)(4m-3n)
=-(8m²-12mn+4n²)-(16m²-9n²)
=-24m²+12mn+5n²