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a fost răspuns

demonstrati identitatile ;
a) (3a+4b)²=9a²+24ab+16b²;
b) (4a+5)·(16a²-20a+25)=64a³+125;

Răspuns :

a)(3a+4b)²=(3a)²+2•3a•4b+(4b)²=9a²+24ab+16b²
b)(4a+5)(16a²-20a+25)=(4a+5)[(4a)²-4a•5+5²]=(4a)³+5³=64a³+125

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