Đáp án:
Tham khảo nha bạn
1. So sánh
a) $10^{10}$ và 48 . $50^{50}$
Ta thấy:
$10^{10}$ < $50^{50}$ (10<50)
⇒ $10^{10}$ < 48 . $50^{50}$
b) $1990^{10}$ + $1990^{9}$ <$1991^{10}$
Ta thấy:
$1990^{10}$ + $1990^{9}$ = $1990^{9}$.1990 + $1990^{9}$
$1991^{10}$ = $1991^{9}$ . 1991
⇔ $1990^{9}$ .1990 < $1991^{9}$ . 1991
⇒ $1990^{10}$ + $1990^{9}$ <$1991^{10}$
c) A = $\frac{3^{10 }. 11+3^{10}.5}{3^{9}. 2^{4}}$ và B = $\frac{2^{10}.13+2^{10}.65}{2^{8}.104}$
A = $\frac{3^{10 }. 11+3^{10}.5}{3^{9}. 2^{4}}$ = $\frac{3^{10}.(11+5)}{3^{9}.2^{4}}$ = $\frac{3^{10}.16}{3^{9}.2^{4}}$ = $\frac{59049.16}{19683.16}$ = $\frac{59049}{19683}$ = 3
B = $\frac{2^{10}.13+2^{10}.65}{2^{8}.104}$ = $\frac{2^{10}.(13+65)}{2^{8}.104}$ = $\frac{2^{10}.78}{2^{8}.104}$ = $\frac{1024.78}{256.104}$ = $\frac{79872}{26624}$ = 3
⇔ 3 = 3
⇒ A = B
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