Câu hỏi của Huỳnh Thị Thảo Nhi

Question

Tìm x:

a, ($\dfrac{1}{3}$+ $\dfrac{1}{6}$) .$2^x$+ $2^{x+1}$=

Nguyễn Lê Phước Thịnh · Accepted Answer

a: $\Leftrightarrow2^x\cdot\dfrac{1}{2}+2^x\cdot2=2^{10}\left(2^2+1\right)$

$\Leftrightarrow2^x=2^{10}\cdot5:\dfrac{5}{2}=2^{10}\cdot5\cdot\dfrac{2}{5}=2^{11}$

=>x=11

b: $\Leftrightarrow3^x\cdot\dfrac{1}{3}+3^x\cdot9=3^{13}\cdot28$

$\Leftrightarrow3^x=3^{13}\cdot28:\dfrac{28}{3}=3^{14}$

hay x=14

Câu trả lời:

a: $\Leftrightarrow2^x\cdot\dfrac{1}{2}+2^x\cdot2=2^{10}\left(2^2+1\right)$

$\Leftrightarrow2^x=2^{10}\cdot5:\dfrac{5}{2}=2^{10}\cdot5\cdot\dfrac{2}{5}=2^{11}$

=>x=11

b: $\Leftrightarrow3^x\cdot\dfrac{1}{3}+3^x\cdot9=3^{13}\cdot28$

$\Leftrightarrow3^x=3^{13}\cdot28:\dfrac{28}{3}=3^{14}$

hay x=14