Question

[ngoc anh nguyen]

tim cac gia tri x nguyen thoa man 

a) | x-1 | < 3

b) x² = -3x

Answer 1

[Đinh Đức Hùng]

a ) \(\left|x-1\right|< 3\)

\(\Leftrightarrow-3< x-1< 3\)

\(\Leftrightarrow-3+1< x< 3+1\)

\(\Leftrightarrow-2< x< 4\)

\(\Rightarrow x=-1;0;1;2;3\)

b ) \(x^2=-3x\)

\(\Leftrightarrow x^2+3x=0\)

\(\Leftrightarrow x\left(x+3\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x+3=0\end{cases}\Rightarrow\orbr{\begin{cases}x=0\\x=-3\end{cases}}}\)