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efectuati utilizind formulele de calcule prescurtat
a)(2-a)(2+3a)
b)(4m+n)cu 2 la patrat


Răspuns :

a) (2-3a)(2+3a)=2²-(3a)²=4-9a²
 
b)(4m+n)²= (4m)²+2×4m×n+n²= 16m²+8mn+n²
b)(4m+n)la patrat=4mla patrat+2imultit4mn+nla patrat