Đáp án:
$\text{Bài tập 1: x = 272.}$
$\text{Bài tập 2:}$
$\text{a) ≈ 7,1.}$
$\text{b) 20 000.}$
$\text{c) 117.}$
Giải thích các bước giải:
$\text{Bài tập 1:}$
$\text{2.x ÷ 34 = $2^{13}÷2^{9}$.}$
$\text{⇒ 2.x ÷ 34 = $2^{4}$.}$
$\text{⇒ 2.x ÷ 34 = 16.}$
$\text{⇒ 2.x = 544.}$
$\text{⇒ x = 544 ÷ 2.}$
$\text{⇒ x = 272.}$
$\text{Vậy x = 272.}$
$\text{Bài tập 2:}$
$\text{a) (45.32 - 43.32) ÷ $3^2$.}$
$\text{= 32.(45 - 43) ÷ $3^2$.}$
$\text{= 32.2 ÷ $3^2$.}$
$\text{= 64 ÷ 9.}$
$\text{≈ 7,1.}$
$\text{b) 53.147 + $53^2$ + 47.200.}$
$\text{= 53.(147 + 53) + 47.200.}$
$\text{= 53.200 + 47.200.}$
$\text{= 200.(53 + 47).}$
$\text{= 200.100.}$
$\text{= 20 000.}$
$\text{c) ($2^{3}$.$9^{4}$ + $9^{3}$.45) ÷ ($9^{2}$.10 - $9^{2}$).}$
$\text{= ($2^{3}$.$9^{4}$ + $9^{3}$.9.5) ÷ ($9^{2}$.10 - $9^{2}$).}$
$\text{= ($2^{3}$.$9^{4}$ + $9^{4}$.5) ÷ ($9^{2}$.10 - $9^{2}$).}$
$\text{= $9^{4}$.($2^{3}$ + 5) ÷ $9^{2}$.(10 - 1).}$
$\text{= $9^{4}$.(8 + 5) ÷ $9^{2}$.(10 - 1).}$
$\text{= $9^{4}$.13 ÷ $9^{2}$.9.}$
$\text{= $9^{4}$.13 ÷ $9^{3}$.}$
$\text{= 6561.13 ÷ 729.}$
$\text{= 85293 ÷ 729.}$
$\text{= 117.}$
