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(a+b+c)*(a+b+c)=?
(a-b+c)*(a-b-c)=?



Răspuns :

(a+b+c)*(a+b+c)=2a+2b+2c=2(a+b+c)
(a+b+c)*(a+b+c) = (a+b+c) la puterea 2
(a-b+c)*(a-b-c)= a la 2 -2ab+b la 2 - c la 2