Bài 1 :
a) \(\left(18+29\right)+\left(158-18-29\right)\)
\(=\left(18-18\right)+\left(29-29\right)+158\)
\(=0+0+158\)
\(=0+158\)
\(=158\)
b) \(\left(-2\right)^2.3+51:\left(-3\right)\)
\(=4.3+-17\)
\(=12+-17\)
\(=-34\)
c) \(-\left(-171+89+223\right)-\left(71-105-111\right)+223\)
\(=\left(-171+71\right)+\left(223-223\right)+105-111\)
\(=100+0+-6\)
\(=94\)
Bài 2 :
\(x+8=-25\)
\(x=-25-8\)
\(x=-\left(25+8\right)\)
\(x=-33\)
Vậy \(x=-33\)
b) \(x+6-\left(-12\right)=33-46\)
\(x+6-12=33-46\)
\(x+18=33-46\)
\(x+18=-13\)
\(x=-18-13\)
\(=-31\)
Vậy \(x=-31\)
c) \(\left(10-4x\right)+120:2^3=17\)
\(\left(10-4x\right)+120:8=17\)
\(\left(10-4x\right)+15=17\)
\(10-4x=17-15\)
\(10-4x=2\)
\(4x=10-2\)
\(4x=8\)
\(x=8:4\)
\(x=2\)
