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Phần đất liền nước ta nằm giữa các vĩ tuyến:

D. 8°34' B - 23°23' B.

a) \(\dfrac{7}{30}+\dfrac{\left(-12\right)}{37}+\dfrac{23}{30}+\dfrac{\left(-25\right)}{37}=\left(\dfrac{7}{30}+\dfrac{23}{30}\right)+\left(\dfrac{-12}{37}+\dfrac{-25}{37}\right)=1+\left(-1\right)=0\)

b) \(\dfrac{5}{7}\cdot\dfrac{5}{11}+\dfrac{5}{7}\cdot\dfrac{2}{11}-\dfrac{5}{7}\cdot\dfrac{14}{11}=\dfrac{5}{7}\cdot\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)=\dfrac{5}{7}\cdot\left(-\dfrac{7}{11}\right)=-\dfrac{5}{11}\)

c) \(\dfrac{\left(-5\right)}{7}\cdot\dfrac{3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+1\dfrac{5}{7}=\dfrac{5}{7}\cdot\dfrac{-3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+\dfrac{12}{7}=\dfrac{5}{7}\cdot\left(\dfrac{-3}{13}-\dfrac{10}{13}\right)+\dfrac{12}{7}=\dfrac{5}{7}\cdot\left(-1\right)+\dfrac{12}{7}=\left(-\dfrac{5}{7}\right)+\dfrac{12}{7}=\dfrac{7}{7}=1\)

đáng lẽ mình cho bn 10 tk nhưng h mình thi xog r

c) Ta có: \(\dfrac{3}{5}+\dfrac{-5}{20}+\dfrac{30}{75}+\dfrac{-7}{4}\)

\(=\dfrac{3}{5}+\dfrac{2}{5}+\dfrac{-1}{4}+\dfrac{-7}{4}\)

\(=1-2=-1\)

Giải:

a)-1/12+4/3=-1/12+16/12=15/12=5/4

b)(-4/14-3/15)-(1/5-20/35-(-1)).7

=-17/35-22/35.7

=-17/35-22/5

=-171/35

c)3/5+-5/20+30/75+-7/4

=3/5+-1/4+2/5+-7/4

=(3/5+2/5)+(-1/4+-7/4)

=1+-2

=-1

d)5/6.-12/14+7/13

=-5/7+7/13

=-16/91

e)2/-9-5/-36-1/4

=-1/12-1/4

=-1/3

f)2/23+-5/12+7/18+21/23+-7/12

=(2/23+21/23)+(-5/12+-7/12)+7/18

=1+-1+7/18

=7/18

Câu 8. Phần đất liền nước ta nằm giữa các vĩ tuyến:

D. 8°34' B - 23°23' B.

các tại hạ cíu tui zớiiiiiiiiiiiiiiiiiiiiiiiii tui sắp phải đi thỉnh kinh òiiii

các tại hạ cíu tui zớiiiiiiiiiiiiiiiiiiiii sắp phải đi thỉnh kinh òi huhuhuhuhu

Sửa đề: \(\frac59\cdot\frac{7}{13}-\frac{30}{23}+\frac69\cdot\frac{5}{13}-\frac{7}{13}\)

\(=\frac{7}{13}\left(\frac59-1\right)-\frac{30}{23}+\frac{30}{117}=\frac{7}{13}\cdot\frac{-4}{9}-\frac{30}{23}+\frac{30}{117}\)

\(=\frac{-52}{117}+\frac{30}{117}-\frac{30}{23}\)

\(=\frac{-22}{117}-\frac{30}{23}=\frac{-22\cdot23-30\cdot117}{23\cdot117}=\frac{-4016}{2691}\)

a) <     b) >     c) <

Bài 1:

a: \(\frac{13}{20}<1\)

\(\frac{19}{20}<1\)

\(\frac{17}{23}<1\)

Do đó: \(\frac{13}{20}+\frac{19}{20}+\frac{17}{23}<1+1+1=3\)

hay \(\frac{13}{20}+\frac{19}{20}+\frac{17}{23}<3\)

b: \(\frac75>1;\frac54>1;\frac98>1;\frac32>1\)

Do đó; \(\frac75+\frac54+\frac98+\frac32>1+1+1+1\)

=>\(\frac75+\frac54+\frac98+\frac32>4\)

Bài 2:

\(\frac87+\frac{11}{13}+\frac{23}{30}+\frac{39}{45}<4\)