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a) (12 m²-5m+n²)-(2n²+6m-3m²)-(12m-mn) =
b) 2x²-4x²+.........+3x²=0


Răspuns :

12m^2-5m+n^2-2n^2+6m-3m^2-12m-mn=9m^2-11m-n^2-mn=m(9m-11)-n(n+m)