Bài 1:

a) \(24 - (-15) - 2\)

\(=39-2\)

\(=37\)

b) \((-85) + 10 - (-85) - 50\)

\(=[(-85)-(-85)]+10-50\)

\(=0+10-50\)

\(=10-50\)

\(=-40\)

c) \(71 - (-30) - (+18) + (-30)\)

\(=[(-30)-(-30)]+71-(+18)\)

\(=0+71-18\)

\(=71-18\)

\(=53\)

d) \(-(30) - (+37) + (+37) + (-85)\)

\(=[-(+37)+(+37)]-(30)+(-85)\)

\(=0-(30)+(-85)\)

\(=(-30)+(-85)\)

\(=-115\)

e) \((35-815) - (795-65)\)

\(=(-780)-730\)

\(=-1510\)

g) \((2002-79+15) + (-79+15)\)

\(=1938+(-64)\)

\(=1874\)

Bài 2:

a) \(25 - (30+x) = x - (27-8)\)

\(25-30-x=x-27+8\)

\(x+x=25-30+27-8\)

\(2x=14\)

\(x=14\div2\)

\(x=7\)

b) \((x-12) - 15 = (20-17) - (18+x) \)

\(x-12-15=13-18-x\)

\(x-27=-5-x\)

\(x+x=-5+27\)

\(2x=22\)

\(x=22\div2\)

\(x=11\)

c) \(15 - x = 7 - (-2)\)

\(15-x=9\)

\(x=15-9\)

\(x=6\)

d) \(x - 35 = (-12) - 3\)

\(x-35=-15\)

\(x=-15+35\)

\(x=20\)

e) \(\left|5-x\right|-26=-15\)

\(\left|5-x\right|=-15+26\)

\(\left|5-x\right|=11\)

Từ đây ta có:

*Nếu \(5-x=11\)

\(x=5-11\)

\(x=-6\)

*Nếu \(5-x=-11\)

\(x=5-(-11)\)

\(x=16\)

Vậy \(x=-6;x=16\)

a)15/8+3/4-5/12

=45+18-10/24

=53/24

b)11/24.12/33+5/6

=11.12/12.2.11.3+5/6

=1/6+5/6

=6/6=1

c)15/8+7/24:5/8

=15/8+7/24.8/5

=15/8+7.8/3.8.5

=15/8+7/15

=đề sai, nếu đúng thì như này

=8/15+7/15

=15/15=1

hbhvgvvggvgbhhgvbnj

nhiều quá :((

\(a,2\left(x-5\right)-3\left(x+7\right)=14\)

\(2x-10-3x-21=14\)

\(-x-31=14\)

\(-x=45\)

\(x=45\)

\(b,5\left(x-6\right)-2\left(x+3\right)=12\)

\(5x-30-2x-6=12\)

\(3x-36==12\)

\(3x=48\)

\(x=16\)

\(c,3\left(x-4\right)-\left(8-x\right)=12\)

\(3x-12-8+x=0\)

\(4x-20=0\)

\(4x=20\)

\(x=5\)

Cố nốt nha bn ! 

cảm ơn, bn nha:)))

mà hình như bạn TOP 3 trả lời câu hỏi pải ko nhỉ???

d, \(-7\left(3x-5\right)+2\left(7x-14\right)=28\)

\(\Leftrightarrow-21x+35+14x-28=28\Leftrightarrow-7x=21\Leftrightarrow x=-3\)

e, \(5\left(3-2x\right)+5\left(x-4\right)=6-4x\)

\(\Leftrightarrow15-6x+5x-20=6-4x\Leftrightarrow-5-x=6-4x\)

\(\Leftrightarrow-11+3x=0\Leftrightarrow x=\frac{11}{3}\)

f, \(-5\left(2-x\right)+4\left(x-3\right)=10x-15\)

\(\Leftrightarrow-10+5x+4x-12=10x-15\Leftrightarrow-22+9x=10x-15\)

\(\Leftrightarrow-7-x=0\Leftrightarrow x=-7\)

a)

\(\frac{x}{18}=\frac{y}{15},x-y=-30\)

\(\frac{x}{18}=\frac{y}{15}\)

\(\frac{x}{18}-\frac{y}{15}=0\)

\(-\frac{6y-5x}{90}=0\)

\(6y-5x=0\)

\(x-y=-30\)

\(-\left(y-x-30\right)=0\)

\(y-x-30=0\)

\(\Rightarrow x=-180;y=-150\)

dẫn tui bài y:9-8=15 với

A) 1000000 - 107492 : 154 x 28 + 1000

= 1000000 - 19544 + 1000

= 981456

B) 8/15 + 4/7 + 14/30 + 12/21 + 5

= 15/7 + 5

= 50/7

C) 9/13 : 6/11 - 5/12 : 6/11

= 9/13 x 11/6 - 5/12 x 11/6

= (9/13 - 5/12) x 11/6

= 43/156 x 11/6

= 473/936

Bài 2

1) X x2 + X x 1/5 = 8/5 

X x (2 + 1/5 ) = 8/5

X x 11/5 = 8/5

X = 8/5 x 5/11

X = 8/11

2) X : 3/8 = 4/3 : 3/6 

X : 3/8 = 8/3

X = 8/3 x 3/8

X = 1

a) 1 000 000 - 107 492 : 154 x 28 + 1000

=  1 000 000 -            698     x 28 + 1000

=  1 000 000 -                    19544 + 1000

=                    980 456                 + 1000

=                                       981 456

b) 8/15 + 4/7 + 14/30 + 12/21 + 5

  = ( 8/15 + 14/30 ) + ( 4/7 + 12/21 ) + 5

  = ( 16/30 + 14/30 ) + ( 12/21 + 12/21 ) + 5

  =            30/30      +          24/21         + 5

  =               1          +         24/21          + 5

  =           ( 1 + 5 ) + 24/21

  =                6      + 24/21

  =                     150/21

 =                         50/7        

1.(18 - 18) x (2 + 8) + ( 4 + 6) + 10 = 30

có rút gọn phân số 35/6 về phân số đc ko ? Nếu có thì mn rút gọn cho mik nhé !

 Ai xong tr tui k cho

khó quá ko làm đc tự đi mà làm