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Question

giúp mình với mai phải học rùi

2$^{x+1}$+2$^{x+2}$+2$^{x+3}$=448

tìm x $\in$ Q

Nguyễn Thị Hồng Nhung · Accepted Answer

$2^{x+1}+2^{x+2}+2^{x+3}=448$

=>$2^x.2+2^x.4+2^x.8=448$

=>$2^x\left(2+4+8\right)=448$

=>$2^x=32$

=>$2^x=2^5$

=>$x=5$

Vậy...Câu trả lời: $2^{x+1}+2^{x+2}+2^{x+3}=448$

=>$2^x.2+2^x.4+2^x.8=448$

=>$2^x\left(2+4+8\right)=448$

=>$2^x=32$

=>$2^x=2^5$

=>$x=5$

Vậy...

Mysterious Person · Answer

ta có : $2^{x+1}+2^{x+2}+2^{x+3}=448$  $\Leftrightarrow2^{x+1}\left(1+2+2^2\right)=448$

$\Leftrightarrow2^{x+1}\left(1+2+4\right)=448\Leftrightarrow2^{x+1}.7=448\Leftrightarrow2^{x+1}=\dfrac{448}{7}$

$\Leftrightarrow2^{x+1}=64\Leftrightarrow2^{x+1}=2^6\Rightarrow x+1=6\Leftrightarrow x=6-1=5$

vậy $x=5$Câu trả lời: ta có : $2^{x+1}+2^{x+2}+2^{x+3}=448$  $\Leftrightarrow2^{x+1}\left(1+2+2^2\right)=448$

$\Leftrightarrow2^{x+1}\left(1+2+4\right)=448\Leftrightarrow2^{x+1}.7=448\Leftrightarrow2^{x+1}=\dfrac{448}{7}$

$\Leftrightarrow2^{x+1}=64\Leftrightarrow2^{x+1}=2^6\Rightarrow x+1=6\Leftrightarrow x=6-1=5$

vậy $x=5$

Đoàn songoku 7a · Answer

$2^{x+1}+2^{x+2}+2^{x+3}=448$

$\Leftrightarrow2^x.2+2^x.2^2+2^{^{ }x}.2^3=448$

$\Leftrightarrow2^x.2+2^{^{ }x}.4+2^x.8=448$

$\Leftrightarrow2^x.\left(2+4+8\right)=448$

$\Leftrightarrow2^x.14=448$

$\Leftrightarrow2^x=448:14$

$\Leftrightarrow2^x=32=2^5$

$\Leftrightarrow x=5$(do x $\ne\pm1;0$)

Vậy .....

Chúc các bạn học tốt !!!Câu trả lời: $2^{x+1}+2^{x+2}+2^{x+3}=448$