Câu hỏi của Doãn Ngọc Oanh

Question

Tổng các số tự nhiên x là bao nhiêu:

( x-4)5 = ( x-4)4

Nguyễn Đức Trí · Accepted Answer

$...\Rightarrow\left(x-4\right)^5-\left(x-4\right)^4=0$

$\Rightarrow\left(x-4\right)^4.\left(x-4-1\right)=0$

$\Rightarrow\left(x-4\right)^4.\left(x-5\right)=0$

$\Rightarrow\left[{}\begin{matrix}x-4=0\x-5=0\end{matrix}\right.$

$\Rightarrow\left[{}\begin{matrix}x=4\x=5\end{matrix}\right.$

$\Rightarrow x\in\left\{4;5\right\}$Câu trả lời: $...\Rightarrow\left(x-4\right)^5-\left(x-4\right)^4=0$

$\Rightarrow\left(x-4\right)^4.\left(x-4-1\right)=0$

$\Rightarrow\left(x-4\right)^4.\left(x-5\right)=0$

$\Rightarrow\left[{}\begin{matrix}x-4=0\x-5=0\end{matrix}\right.$

$\Rightarrow\left[{}\begin{matrix}x=4\x=5\end{matrix}\right.$

$\Rightarrow x\in\left\{4;5\right\}$