Question

Tìm x:

x² - 2x = 24

Answer 1

x² - 2x = 24

\(\Leftrightarrow\) x² - 2x - 24 = 0

\(\Leftrightarrow\) x² - 2x + 1 - 25 = 0

\(\Leftrightarrow\) (x - 1)² - 25 = 0

\(\Leftrightarrow\) (x - 1 - 5)(x - 1 + 5) = 0

\(\Leftrightarrow\) (x - 6)(x + 4) = 0

\(\Leftrightarrow\) \(\left[{}\begin{matrix}x-6=0\\x+4=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-4\end{matrix}\right.\)

Vậy S = {6; -4}

Chúc bn học tốt! (Miyuki Misaki làm sai rồi nha, x-1 ko phải x+1 :v)