Question

[Trong Vu]

Tìm số tự nhiên x thỏa mãn : 

a) (2x+3).(5x-15)=0               b) (3x+1).(3x-9)=0

Answer 1

[ILoveMath]

a) \(\Leftrightarrow\left[{}\begin{matrix}2x+3=0\\5x-15=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{3}{2}\\x=3\end{matrix}\right.\)

b) \(\Leftrightarrow\left[{}\begin{matrix}3x+1=0\\3x-9=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{3}\\x=3\end{matrix}\right.\)

Answer 2

[nthv_.]

a. \(\left[{}\begin{matrix}2x+3=0\\5x-15=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-3}{2}\\x=3\end{matrix}\right.\)

b. \(\left[{}\begin{matrix}3x+1=0\\3x-9=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-1}{3}\\x=3\end{matrix}\right.\)