Nhớ rút gọn

a giỏi quá

Rút gon nữa là: \(\dfrac{5}{8}\)

\(\dfrac{7}{8}.\dfrac{5}{7}=\dfrac{1.5}{8.1}=\dfrac{5}{8}\)

\(x\in\left\{10;15;30\right\}\)

e. (x² - 4x + 16)(x - 4) - (x² + x)(x - 4) = 33x - 66

<=> (x² - 4x + 16 - x² - x)(x - 4) = 33x - 66

<=> (-5x + 16)(x - 4) = 33x - 66

<=> -5x² + 20x + 16x - 64 = 33x - 66

<=> -64 + 66 = 5x² - 20x - 16x

<=> 5x² - 36x = 2

<=> x(5x - 36) = 2

<=> \(\left[{}\begin{matrix}x=1\\5x-36=2\\x=2\\5x-36=1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=7,6\\x=2\\x=7,4\end{matrix}\right.\)

Đề đâu bn nhỉ

Anh giỏi quá