Câu hỏi của George H. Dalton

Question

Tính $\dfrac{5.4^{15}-9^9-4.3^{20}.8^9}{5.2^9.6^{19}-7.2^{29}.27^6}$

Nguyễn Lê Phước Thịnh · Accepted Answer

Sửa đề:$\dfrac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^9\cdot6^{19}-7\cdot2^{29}\cdot27^6}$

$=\dfrac{5\cdot2^{30}\cdot3^{18}-3^{20}\cdot2^{29}}{5\cdot2^9\cdot3^{19}\cdot2^{19}-7\cdot2^{29}\cdot3^{18}}$

$=\dfrac{3^{18}\cdot2^{29}\cdot\left(5\cdot2-9\right)}{2^{28}\cdot3^{18}\cdot\left(5\cdot3-7\cdot2\right)}=2$

Câu trả lời:

Sửa đề:$\dfrac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^9\cdot6^{19}-7\cdot2^{29}\cdot27^6}$

$=\dfrac{5\cdot2^{30}\cdot3^{18}-3^{20}\cdot2^{29}}{5\cdot2^9\cdot3^{19}\cdot2^{19}-7\cdot2^{29}\cdot3^{18}}$

$=\dfrac{3^{18}\cdot2^{29}\cdot\left(5\cdot2-9\right)}{2^{28}\cdot3^{18}\cdot\left(5\cdot3-7\cdot2\right)}=2$