Đáp án:
Giải thích các bước giải:
Bài 1:
`a,5-x=17-(-5)`
`\to 5-x=17+5`
`\to 5-x=22`
`\to -x=22-5`
`\to-x=17`
`\to x=-17`
Vậy `x=-17`
,
`b,x-12=(-9)-(-15)`
`\to x-12=-9+15`
`\to x-12=6`
`\to x=6+12`
`\to x=8`
Vậy `x=8`
,
`c,9-25=(-7-x)-(25-7)`
`\to 9=-7-x-25+7+25`
`\to -x=9`
`\to x=-9`
Vậy `x=-9`
,
`d,11+(15-11)=x-(25-9)`
`\to 11+15-11=x-25+9`
`\to 15=x-16`
`\to x=15+16`
`\to x=31`
Vậy `x=31`
,
`e,17-{-x-[-x-(-x)]}=-16`
`\to 17-[-x-(-x+x)]=-16`
`\to 17-(-x-0)=-16`
`\to 17+x=-16`
`\to x=-16-17`
`\to x=-33`
Vậy `x=-33`
,
`f,x+{(x+3)-[(x+3)-(-x-2)]}=x`
`\to [x+3-(x+3+x+2)=x-x`
`\to x+3-x-3-x-2=0`
`\to -x-2=0`
`\to -x=2`
`\to x=-2`
Vậy `x=-2`
Bài 2 :
`a,2075+37-2076-47`
`=-1-10`
`=-11`
,
`b,34+35+36+37-14-15-16-17`
`=(34-14)+(35-15)+(36-16)+(37-17)`
`=20+20+20+20`
`=80`
,
`c,-7624+(1543+7624)`
`=-7624+1543+7624`
`=1543`
,
`d,(27-514)-(486-73)`
`=27-514-486+73`
`=(27+73)+(-514-486)`
`=100-1000`
`=-900`
Bài 3 :
`a,x+45-[90+(-20)+5-(-45)]`
`=x+45-(90-20+5+45)`
`=x+45-90+20-5-45`
`=x-75`
,
`b,x+(294+13)+(94-13)`
`=x+294+13+94-13`
`=x+388`
Bài 4:
`a,-b-(b-a+c)`
`=-b-b+a-c`
`=-2b+a-c`
,
`b,-(a-b+c)-(c-a)`
=-a+b-c-c+a`
`=b-2c`
,
`c,b-(b+a-c)`
`=b-b-a+c`
`=-a+c`
,
`d,a-(-b+a-c)`
`=a+b-a+c`
`=b+c`
