bằng 13/15 bạn ạ 

a=-11/13

các bạn cho mình xin lời giải cụ thể với ạ

A=1/3-1/3-(3/5-3/5)+(5/7-5/7)-(7/9-7/9)+(9/11-9/11)-11/13

A=0-0+0-0+0-11/13

A=-11/13

\(\frac{1}{3}-\frac{3}{5}+\frac{5}{7}-\frac{7}{9}+\frac{9}{11}-\frac{11}{13}+\frac{13}{15}+\frac{11}{13}-\frac{9}{11}+\frac{7}{9}-\frac{5}{7}+\frac{3}{5}\)

\(=\left(-\frac{3}{5}+\frac{3}{5}\right)+\left(\frac{5}{7}-\frac{5}{7}\right)+\left(-\frac{7}{9}+\frac{7}{9}\right)+\left(\frac{9}{11}-\frac{9}{11}\right)+\left(-\frac{11}{13}+\frac{11}{13}\right)+\left(\frac{1}{3}+\frac{13}{15}\right)\)

\(=\frac{1}{3}+\frac{13}{15}\)

\(=\frac{6}{5}\)

\(\frac{1}{3}-\frac{3}{5}+\frac{5}{7}-\frac{7}{9}+\frac{9}{11}-\frac{11}{13}-\frac{9}{11}+\frac{7}{9}-\frac{5}{7}+\frac{3}{5}-\frac{1}{3}\)

\(=\left(\frac{1}{3}-\frac{1}{3}\right)+\left(\frac{3}{5}-\frac{3}{5}\right)+\left(\frac{5}{7}-\frac{5}{7}\right)+\left(\frac{7}{9}-\frac{7}{9}\right)+\left(\frac{9}{11}-\frac{9}{11}\right)-\frac{11}{13}\)

\(=0+0+0+0+0-\frac{11}{13}=-\frac{11}{13}\)

\(\frac{1}{3}-\frac{3}{5}+\frac{5}{7}-\frac{7}{9}+\frac{9}{11}+\frac{7}{9}-\frac{5}{7}+\frac{3}{5}-\frac{1}{3}\)

\(=\left(\frac{1}{3}-\frac{1}{3}\right)+\left(\frac{3}{5}-\frac{3}{5}\right)+\left(\frac{5}{7}-\frac{5}{7}\right)+\left(\frac{7}{9}-\frac{7}{9}\right)-\frac{11}{13}\)

\(=0+0+0+0+0-\frac{11}{13}=-\frac{11}{13}\)

XL mik thiếu 9/11 nha. Bài bạn dcv new lm đúng r

a) = 1.1204
b) = 0.5714

a) = 1.1204
b) = 0.5714

a) = 1.1204
b) = 0.5714

1) 5 + (-4) = 1

2) (-8) + 2 = -6

3) 8 + (-2) = 6

4) 11 + (-3) = 8

5) (-11) + 2 = -9

6) (-7) + 3 = -4

7) (-5) + 5 = 0

8) 11 + (-12) = -1

9) (-18) + 20 = 2

10) (15) + (-12) = 3

11) (-17) + 17 = 0

12) 16 + (-2) = 14

13) (30) + (-14) = 16

14) (-19) + 20 = 1

15) (-18) + 15 = -3

16) (10) + (-6) = 4

17) (-28) + 14 = -14

18) 15 + (-30) = -15

19) (15) + (-4) = 11

20) (-21) + 11 = -10

21) 8 + (-22) = -14

22) (-15) + 4 = -11

23) (-3) + 2 = -1

24) 17 + (-14) = 3

25) 17 + (-14) = 3

thế này đọc đc mới đỉnh

tách ra bn

khó nhìn quá:V

Chóng mặttttttttttttttt!

\(M=\left(\frac{3}{5}+\frac{4}{5}\right)+\left(\frac{3}{7}+\frac{4}{7}\right)-\left(\frac{3}{11}+\frac{4}{11}\right)\)

\(=\frac{7}{5}+1-\frac{7}{11}\)

\(\frac{12}{5}-\frac{7}{11}\)

\(=......t\text{ự}t\text{ính}nh\text{á}\)

\(=\frac{3}{5}+\frac{3}{7}-\frac{3}{11}+\frac{4}{5}+\frac{4}{7}-\frac{4}{11}\)

\(=\left(\frac{3}{5}+\frac{4}{5}\right)+\left(\frac{3}{7}+\frac{4}{7}\right)-\left(\frac{3}{11}+\frac{4}{11}\right)\)

\(=\frac{7}{5}+1-\frac{7}{11}\)

\(=\frac{12}{5}-\frac{7}{11}\)

\(=\frac{97}{55}\)

A.3/7

B.3/5

C.5/7

D.11/2

k hộ mình nha!