Bài 6: Tính chất của phép cộng các số nguyên

\(\left(1+3+5+7+...+99\right)-\left(2+4+6+...+100\right)\\ =4950-2550\\ =2400\)

=(-2)+(-2)+...+(-2)

=(-2)*25=-50

`= - (1+2+...+99)`

Số số hạng: `(99-1) : 1 +1 = 99`

Tổng: `(99+1) . 99 : 2 = 4950`

`-> A = -4950`

Câu 2: 

a: x-1/2=-3/4

=>x=-3/4+1/2=-3/4+2/4=-1/4

b: x+7/5=1/10

=>x=1/10-7/5=1/10-14/10=-13/10

c: -1/12-x=3/8

=>x=-1/12-3/8=-2/24-9/24=-11/24

1. 13/25; -31/29; 7/8; 11/24; 35/41

2. \(a)x=-3/4-(-1/2)=-3/4+1/2=-3/4+2/4=-1/4\)

\(b)x=1/10+(-7/5)=1/10+(-14/10)=-13/10\)

\(c)x=-1/12-3/8=-2/24-9/24=-11/24\)

câu 1 :

số đối của p/số \(\dfrac{13}{-25}\) là \(\dfrac{-13}{-25}\)

........................ \(\dfrac{31}{29}\) là \(\dfrac{-31}{29}\)

........................ \(\dfrac{7}{-8}\) là \(\dfrac{-7}{-8}\)

........................ - \(\dfrac{11}{24}\) là \(\dfrac{-11}{24}\) hoặc \(\dfrac{11}{-24}\)

........................ \(\dfrac{-35}{41}\) là \(\dfrac{35}{41}\)

câu 2 :

a, x-1/2=-3/4

=>x=-3/4+1/2=-3/4+2/4=-1/4

b, x+7/5=1/10

=>x=1/10-7/5=1/10-14/10=-13/10

c,  -1/12-x=3/8

=>x=-1/12-3/8=-2/24-9/24=-11/24

bạn ghi lại đề đi bạn

6: =>x=9/10+1/5=9/10+2/10=11/10

7: =>x=3/8-5/12=36/96-40/96=-1/24

8: =>x=7/6-5/4=14/12-15/12=-1/12

9: =>x=1/35+2/7=1/35+10/35=11/35

10: =>x=2/7-7/10=20/70-49/70=-29/70

1, \(x=-\dfrac{5}{3}-\dfrac{1}{2}=-\dfrac{10}{6}-\dfrac{3}{6}=-\dfrac{13}{6}\)

2, \(x=\dfrac{1}{3}-\dfrac{3}{5}=\dfrac{5-9}{15}=-\dfrac{4}{15}\)

4, \(x=-\dfrac{7}{9}+\dfrac{4}{3}=\dfrac{-7+12}{9}=\dfrac{5}{9}\)

5, \(x=\dfrac{5}{6}-\dfrac{7}{3}=\dfrac{5-14}{6}=-\dfrac{9}{6}=-\dfrac{3}{2}\)

6, \(x=\dfrac{9}{10}+\dfrac{1}{5}=\dfrac{9+2}{10}=\dfrac{11}{10}\)

7, \(x=\dfrac{3}{8}-\dfrac{5}{12}=\dfrac{9-10}{12}=-\dfrac{1}{12}\)

8, \(x=\dfrac{7}{6}-\dfrac{5}{4}=\dfrac{14-15}{12}=-\dfrac{1}{12}\)

9, \(x=\dfrac{1}{35}+\dfrac{2}{7}=\dfrac{1+10}{35}=\dfrac{11}{35}\)

10, \(x=-\dfrac{7}{10}+\dfrac{2}{7}=\dfrac{-49+20}{70}=\dfrac{-29}{70}\)

6, \(x=\dfrac{9}{2}+\dfrac{1}{2}=\dfrac{10}{2}=5\)

7, \(x=-\dfrac{3}{4}-\dfrac{5}{4}=-\dfrac{8}{4}=-2\)

8, \(x=\dfrac{5}{7}-\dfrac{2}{7}=\dfrac{3}{7}\)

9, \(x=\dfrac{1}{3}+\dfrac{4}{3}=\dfrac{5}{3}\)

10, \(x=-\dfrac{7}{2}-\dfrac{5}{2}=-\dfrac{12}{2}=-6\)

\(6,x-\dfrac{1}{2}=\dfrac{9}{2}\Leftrightarrow x=5\)

\(7,x+\dfrac{5}{4}=\dfrac{-3}{4}\Leftrightarrow x=-2\)

\(8,x+\dfrac{2}{7}=\dfrac{5}{7}\Leftrightarrow x=\dfrac{3}{7}\)

\(9,x-\dfrac{4}{3}=\dfrac{1}{3}\Leftrightarrow x=\dfrac{5}{3}\)

\(10,x+\dfrac{5}{2}=\dfrac{-7}{2}\Leftrightarrow x=-6\)

\(x-\dfrac{1}{2}=\dfrac{9}{2}\)

\(x\)        \(=\dfrac{9}{2}+\dfrac{1}{2}=\dfrac{10}{2}=5\)

\(x+\dfrac{5}{4}=\dfrac{-3}{4}\)

\(x\)        \(=\dfrac{-3}{4}+\dfrac{-5}{4}=\dfrac{-8}{4}=-2\)

\(x+\dfrac{2}{7}=\dfrac{5}{7}\)

\(x\)        \(=\dfrac{5}{7}+\dfrac{-2}{7}=\dfrac{3}{7}\)

\(x-\dfrac{4}{3}=\dfrac{1}{3}\)

\(x\)         \(=\dfrac{1}{3}+\dfrac{4}{3}=\dfrac{5}{3}\)

\(x+\dfrac{5}{2}=\dfrac{-7}{2}\)

\(x\)        \(=\dfrac{-7}{2}+\dfrac{-5}{2}=\dfrac{-12}{2}=-6\)

1, \(x=-\dfrac{7}{3}-\dfrac{1}{3}=-\dfrac{8}{3}\)

2, \(x=\dfrac{1}{8}-\dfrac{3}{8}=-\dfrac{2}{8}=-\dfrac{1}{4}\)

3, \(x=\dfrac{6}{5}+\dfrac{4}{5}=\dfrac{10}{5}=2\)

4, \(x=\dfrac{7}{3}-\dfrac{2}{3}=\dfrac{5}{3}\)

5, \(x+\dfrac{7}{3}=\dfrac{5}{3}\Leftrightarrow x=\dfrac{5}{3}-\dfrac{7}{3}=-\dfrac{2}{3}\)

\(=x+\dfrac{1}{3}=\dfrac{-7}{3}\Leftrightarrow x=\dfrac{-8}{3}\)

\(=\dfrac{1}{8}-x=\dfrac{3}{8}\Leftrightarrow x=\dfrac{-1}{4}\)

\(=x-\dfrac{4}{5}=\dfrac{6}{5}\Leftrightarrow x=2\)

\(=\dfrac{2}{3}+x=\dfrac{7}{3}\Leftrightarrow x=\dfrac{5}{3}\)

\(=x-\dfrac{-7}{3}=\dfrac{5}{3}\Leftrightarrow x=\dfrac{-2}{3}\)

1)x=-7/3-1/3

   x=-8/3

2)x=1/8-3/8

   x=-1/4

3)x=6/5+4/5

   x=2

4)x=7/3-2/3

   x=5/3

5)x=5/3+(-7/3)

   x=-2/3

Zui lòng chia nhỏ

1: =>x=-5/3-1/2=-13/6

2: =>x=1/3-3/5=-4/15

4: =>x=-7/9+4/3=-7/9+12/9=5/9

5: =>x=5/6-7/3=5/6-14/6=-9/6=-3/2

6: =>x=9/10+1/5=11/10

7: =>x=3/8-5/12=36/96-40/96=-1/24

8: Đề sai rồi bạn

Diện tích thửa ruộng là:

110x78=8580(m²)=0,858(ha)

Khối lượng thóc thu được là:

0,858x71,5=61,347(tạ)