Bài 6.
a.(x + 17)-24+35
x + 17 -24+35
x + 28
b.(-32)-(y + 20)+20
-32 - y - 20+20
y-(32+20-20)
y-32
bài 7.
a.(3567-214)-3567
(3567-3567)-214
0-214
-214
b.(-2017)-(28-2017)
(-2017)-28+2017
[(-2017)+2017]-28
0-28
-28
c.-(269-375)+(269-375)
0
d.(123+345)+(456-123)-[2017-(-345)]
123+345+456-123-2017-345
(123-123)+(345-345)+456-2017
0+0+456-2017
-1561
Bài 10:
a.15-(4-x)=6
4-x=15-6
4-x=9
x=4-9
x=-5
b.-30+(25-x)=-1
25-x=(-1)-(-30)
25-x=29
x=25-29
x=-4
c.x-(12-25)=-8
x-(-13)=-8
x+13=-8
x=-8-13
x=-21
d.(x-29)-(17-38)=-9
(x-29)-(-21)=-9
(x-29)+21=-9
x-29=-9-21
x-29=-30
x=-30+29
x=-1
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