Bài tập 1 :
1) ( -25 ) + ( -14 )
= ( - 25 ) - 14
= -39
2) ( -38 ) + ( -72 )
= ( - 38 ) - 72
= -110
3) ( -23 ) + ( + 14 )
= ( -23 ) + 14
= -9
4) ( + 32 ) + ( -52 )
= 32 - 52
= -20
5) ( -21 ) + ( +14 )
= ( -21 ) + 14
= -7
6) ( +16 ) + ( +52 )
= 16 + 52
= 68
7) ( -32 ) + ( -14 )
= ( -32) - 14
= -46
8) ( -59 ) + ( -20 )
= ( -59 ) - 20
= -79
10) ( -73 ) + ( +7 )
= ( -73 ) + 7
= -66
11) 10 - ( -6 )
= 10 + 6
= 16
12) ( -28 ) - 14
= -42
13) 15 - ( -30 )
= 15 + 30
= 45
14) ( +11 ) . ( -11 )
= -121
15) ( -17 ) . ( -3 )
= 51
16) ( -17 ) . ( -14 )
= 238
17) ( -15 ) . ( -4 )
= 60
18) ( -21 ) . 11
= -231
19) 8 . ( -22 )
= -176
Bài tập 2 :
1) ( -37 ) + 14 + 26 + 37
= 14 + 26
= 40
2) ( -24 ) + 6 + 10 + 24
= 6 + 10
= 16
3) 15 + 23 + ( -25 ) + ( -23 )
= 15 + ( -25 )
= -10
4) 60 + 33 + ( -50 ) + ( -33 )
= 60 + ( -50 )
= 10
5) ( -16 ) + ( -209 ) + ( -14 ) +209
= ( -16 ) + ( -14 )
= -30
6) ( -12 ) + ( -13 ) + 36 + ( -11 )
= -36 + 36
= 0
7) -7264 + ( 1543 +7264 )
= -7264 + 1543 + 7264
= 1543
8) ( 144 - 97 ) - 144
= 144 - 97 - 144
= 97
9) ( -145 ) - ( 18 -145 )
= ( -145 ) - 18 + 145
= -18
Bài tập 3 :
a) -16 + 23 + x = -16
<=> x = -16 + 16 - 23
<=> x = -23
b) 3x + 17 = 12
<=> 3x = -5
<=> x= $\frac{-5}{3}$
c) | x - 1 | = 2
<=> \(\left[ \begin{array}{l}x-1=2\\x-1=-2\end{array} \right.\)
<=> \(\left[ \begin{array}{l}x=3\\x=-1\end{array} \right.\)
