Bài 2:
a: \(\left(2x-3\right)-\left(x-2\right)=-99-98\)
=>\(2x-3-x+2=-197\)
=>x-1=-197
=>x=-197+1=-196
b: \(\left|x-3\right|-\left(-\left|-7\right|\right)=\left|-17\right|+\left(-5\right)-\left|3\right|\)
=>\(\left|x-3\right|-\left(-7\right)=17-5-3\)
=>\(\left|x-3\right|+7=17-8=9\)
=>\(\left|x-3\right|=2\)
=>\(\left[{}\begin{matrix}x-3=2\\x-3=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=1\end{matrix}\right.\)
c: \(10-\left(-\left|x+5\right|\right)=\left|-15\right|-\left(-8\right)\)
=>\(10+\left|x+5\right|=15+8=23\)
=>\(\left|x+5\right|=23-10=13\)
=>\(\left[{}\begin{matrix}x+5=13\\x+5=-13\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=8\\x=-18\end{matrix}\right.\)
Bài 3:
M>N
=>a+b-1>b+c-1
=>a+b>b+c
=>a+b-b-c>0
=>a-c>0
=>a-c dương
Bài 1:
a: \(10000-\left(509-374\right)-\left(-109+274\right)\)
\(=10000-509+374+109-274\)
\(=10000-\left(509-109\right)+\left(374-274\right)\)
\(=10000-400+100=9700\)
b: \(215+\left(-38\right)-\left(-58\right)+90-85\)
\(=215-38+58+5\)
\(=\left(215+5\right)+\left(58-38\right)\)
=220+20
=240
