Question

[Lê Thuy Linh]

Tìm số nguyên x, biết:

a) | 3x + 1|= 4

b) | x+2 | = x - 3

c) ( 8 - x ) (3x + 3) ( x-4) = 0

x^3 +3x = 0

Answer 1

[Lê Thuy Linh]

câu cuối là d)

Answer 2

[Sakuraba Laura]

a) 

\(|3x+1|=4\)

\(\Rightarrow\orbr{\begin{cases}3x+1=4\\3x+1=-4\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}3x=4-1\\3x=-4-1\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}3x=3\\3x=-5\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=3\div3\\x=-5\div3\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=1\\x=-1,6667\end{cases}}\)

Vậy x = 1