Question

Tìm x \(\in\) Z, biết x²⁰ - x¹⁸ = 0

Answer 1

\(x^{20}-x^{18}=0\)

\(\Rightarrow x^{18}\left(x^2-1\right)=0\)

\(\Rightarrow\left[\begin{matrix}x^{18}=0\\x^2-1=0\end{matrix}\right.\)

\(\Rightarrow\left[\begin{matrix}x=0\\x^2=1\end{matrix}\right.\)\(\Rightarrow\left[\begin{matrix}x=0\\x=1\\x=-1\end{matrix}\right.\)

Answer 2

x²⁰ - x¹⁸ = 0

=> x²⁰ = x¹⁸

Mà 1²⁰ = 1¹⁸ hoặc 0²⁰ = 0¹⁸

=> x thuộc {0;1}

Answer 3

xin lỗi, thiếu tg đề bài là nguyên dương

Answer 4

x^20-x^18=0
=> x^20=x^18
=>x^18.x^2=x^18.1
hoac x^18.x^2=x^18
+)x^18.x^2=x^18.1
=>x^2=1
=>x=1
+)x^18.x^2=x^18
=>x^2=0
=>x=0
Vay x=0 hoac x=1