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Daca a-b=2^-1, calculati 4a^2 +4b^2 -8ab-1

Răspuns :

a -b = 1/2
4(a²-2ab + b²) - 1 = 2² ·(a-b)² -1 = [2(a-b) +1]·[2(a-b) -1]= (1+1)(1-1) = 0