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1 . Efectuati , dand factor comun  :
a ) 2005^2004 - 2004 x 2005^2003
b ) 5^3 x 2^6 - 5^3 x 7^2
 
2 . Calculati x astfel incat  : 3^37 - 27^12 = 2 x 81^10 : x^2 .


Răspuns :

[tex]1 \ a) 2005^{2004}-2004*2005^{2003}= \\\\=2005^{2003} (2005-2004*1)= \\\\= 2005^{2003}(2005-2004)= \\\\ =2005^{2003}*1= \\\\ =\boxed{2005^{2003}}[/tex]

[tex]b) 5^3*2^6-5^3*7^2= \\\\ =5^3(2^6-7^2)= \\\\ =5^3(64-49)= \\\\ =125*15= \\\\=\boxed{1875}[/tex]

[tex]2) 3^{37}-27^{12}=2*81^10:x^2 \\\\ 3^{37}-(3^3)^{12}=2*(3^4)^{10}:x^2 \\\\ 3^{37}-3^{36}=2*3^{40} :x^2\\\\ 3^{36}(3-1)=2*3^{40}:x^2 \\\\ 3^{36}*2=2*3^{40}:x^2 \\\\ 3^{36}=3^{40}:x^2 \\\\ x^2=3^{40}:3^{36} \\\\ x^2= 3^4 \\\\ x^2= (3^2)^2 \\\\ x^2=9^2 \\\\ \boxed{x=9}[/tex]