Bạn tham khảo :
$a,$
$10^6 : 10^4 = 10^{6-4} =10^2$
$b,$
$5^8: 25^2 = 5^8: (5^2)^2 = 5^8 : 5^4 = 5^{8-4} = 5^4$
$c,$
$19^7:19^3 = 19^{7-3} = 19^4$
$2^ 1+ 2+ 2^ x+1 + 2^ x+ 1= 57$
$⇒ 2^ 3+ 2^ x. 2+ 2^ x+ 1= 57$
$⇒ 8 + 2^ x. ( 2+ 1) + 1= 57$
$⇒ 2^ x. 3+ 9= 57$
$⇒ ( 2^ x) . 3= 57 - 9$
$⇒ (2^x).3 = 48$
$2^ x= 48 :3$
$2^ x= 16$
$2^ x= 2^ 4$
$x= 4$
- So sánh các số :
$a,$
Ta có :
$9^{12} = (3^2)^12 = 3^{24}$
$27^7 = (3^3)^7 = 3^{21}$
⇒ $ 3^{24} > 3^{21} ⇒ 9^{12} > 27^7$
$b,$
Ta có :
$125 ^{80} = ( 5^ 3)^80= 5^{240}$
$25^{118}= ( 5^2)^{118} = 5^{236}$
⇒ $5^{240} > 5^{236} ⇒ 125^{80} > 25^{118}$
$c,$
Ta có :
$625^{10} = (5^4)^{10} = 5^{40}$
⇒ $5^{40} = 5^{40} ⇒ 625^{10} = 5^{40}$
