Question

Tìm các số nguyên x, biết:

a) 7x . ( x - 10 ) = 0

b) 17 . ( 3x - 6 ) . ( 2x - 18 ) =0

c) ( 4 - 2x ) . ( x - 3 ) = 0

d) - x . ( x + 7 ) . ( x - 4 ) = 0

Answer 1

a, 7\(x\).(\(x\) - 10) = 0

   \(\left[{}\begin{matrix}7x=0\\x-10=0\end{matrix}\right.\)

    \(\left[{}\begin{matrix}x=0\\x=10\end{matrix}\right.\)

Vậy \(x\in\) {0; 10}

Answer 2

b, 17.(3\(x\) - 6).(2\(x\) - 18) = 0

    \(\left[{}\begin{matrix}3x-6=0\\2x-18=0\end{matrix}\right.\)

    \(\left[{}\begin{matrix}3x=6\\2x-18=0\end{matrix}\right.\)

     \(\left[{}\begin{matrix}x=6:3\\x=18:2\end{matrix}\right.\)

       \(\left[{}\begin{matrix}x=2\\x=9\end{matrix}\right.\)

Answer 3

c, (4 - 2\(x\)).(\(x\) - 3) = 0

    \(\left[{}\begin{matrix}4-2x=0\\x-3=0\end{matrix}\right.\)

    \(\left[{}\begin{matrix}2x=4\\x=3\end{matrix}\right.\)

    \(\left[{}\begin{matrix}x=4:2\\x=3\end{matrix}\right.\)

     \(\left[{}\begin{matrix}x=2\\x=3\end{matrix}\right.\)

    Vậy \(x\in\) {2; 3}

Answer 4

d, - \(x\).(\(x\) + 7).(\(x\)  - 4) = 0

   \(\left[{}\begin{matrix}x=0\\x+7=0\\x-4=0\end{matrix}\right.\)

    \(\left[{}\begin{matrix}x=0\\x=-7\\x=-4\end{matrix}\right.\)

  Vậy \(x\in\) {-4; -7; 0}