a/ \(\left|a-1\right|+\left|b+2\right|=0\)
Mà \(\left\{{}\begin{matrix}\left|a-1\right|\ge0\\\left|b+2\right|\ge0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left|a-1\right|=0\\\left|b+2\right|=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}a-1=0\\b+2=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}a=1\\b=-2\end{matrix}\right.\)
Vậy ...
b/ \(2-3+4-5+...........+2016-2017+2018\)
\(=\left(2-3\right)+\left(4-5\right)+.........+\left(2016-2017\right)+2018\)
\(=\left(-1\right)+\left(-1\right)+......+\left(-1\right)+2018\)
\(=\left(-1\right).1008+2018\)
\(=1010\)
Đúng 0
Bình luận (1)
