Bài 1 :
a, | -75 | - | -50 |
= 75 - 50
= 25
b, | 25 | - | -15 |
= 25 - 15
= 10
c, | -4 | + | -10 |
= 4 + 10
= 14
d, | -105 | + | -95 |
= 105 + 95
= 200
Bài 2 :
a, | x + 1 | - 7 = | 20 |
| x + 1 | = 20 - 7
| x + 1 | = 13
`=>` \(\left[ \begin{array}{l}x+1=13\\x+1=-13\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=12\\x=-14\end{array} \right.\)
Vậy x ∈ { 12 ; -14 }
b, | 8 - x | = | -5 |
| 8 - x | = 5
`=>` \(\left[ \begin{array}{l}8-x=5\\8-x=-5\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=3\\x=13\end{array} \right.\)
Vậy x ∈ { 3 ; 13 }
c, | x + 3 | + | 150 | = 200
| x + 3 | + 150 = 200
| x + 3 | = 50
`=>` \(\left[ \begin{array}{l}x+3=50\\x+3=-50\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=47\\x=-53\end{array} \right.\)
Vậy x ∈ { 47 ; -53 }
