Tất cả đều đúng nhé 

tất cả đều đúng

a Đ

b S

c S

d Đ

a ) S 

b ) Đ

c ) S

d ) Đ

k cho mk nhé 

a)\(\dfrac{5}{7}+\dfrac{4}{9}=\dfrac{45}{63}+\dfrac{28}{63}=\dfrac{73}{63}\) ; \(\dfrac{9}{11}+\dfrac{3}{8}=\dfrac{72}{88}+\dfrac{33}{88}=\dfrac{105}{88}\)

\(\dfrac{4}{5}-\dfrac{2}{3}=\dfrac{12}{15}-\dfrac{10}{15}=\dfrac{2}{15}\); \(\dfrac{16}{25}-\dfrac{2}{5}=\dfrac{16}{25}-\dfrac{10}{25}=\dfrac{6}{25}\)

b)\(5+\dfrac{3}{5}=\dfrac{25}{5}+\dfrac{3}{5}=\dfrac{28}{5};10-\dfrac{9}{16}=\dfrac{160}{16}-\dfrac{9}{16}=\dfrac{151}{16}\)

\(\dfrac{2}{3}-\left(\dfrac{1}{6}+\dfrac{1}{8}\right)=\dfrac{2}{3}-\left(\dfrac{8}{48}+\dfrac{6}{48}\right)=\dfrac{2}{3}-\dfrac{14}{48}=\dfrac{32}{48}-\dfrac{14}{48}=\dfrac{3}{8}\)

a) Đ

b) S

c) Đ

d) S

~Học tốt~

a) Đ

b) S

c) Đ

d) S

=^_^=

k mình nha

=1 nha

bằng 1 nhé bạn

Gợi ý: Rút gọn 2 ps, quy đồng rồi so sánh.

15/50 ? 90/45 ra 0.26<2

\(\frac{1}{2}:\frac{3}{2}:\frac{5}{4}:\frac{6}{5}:\frac{7}{6}:\frac{8}{7}\)

\(=\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{4}{5}\cdot\frac{5}{6}\cdot\frac{6}{7}\cdot\frac{7}{8}\)

\(=\frac{1\cdot\left(2\cdot5\cdot6\cdot7\right)}{8\cdot3\cdot\left(2\cdot5\cdot6\cdot7\right)}\)

\(=\frac{1}{24}\)

\(\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot\frac{4}{5}\cdot\frac{5}{6}\cdot\frac{6}{7}\cdot\frac{7}{8}\cdot\frac{8}{9}\cdot\frac{9}{10}\)

\(=\frac{1\cdot\left(2\cdot3\cdot4\cdot5\cdot6\cdot7\cdot8\cdot9\right)}{\left(2\cdot3\cdot4\cdot5\cdot6\cdot7\cdot8\cdot9\right)\cdot10}\)

\(=\frac{1}{10}\)

Đáp án của câu hỏi trên là "đúng".

Chúc bạn học tốt.

😁😁😁

B)  sai

C) đúng

D) sai

Bài 5

\(y+\frac{3}{4}=\frac{2}{5}+1\)

\(\Leftrightarrow y=\frac{2}{5}+1-\frac{3}{4}\)

\(\Leftrightarrow y=\frac{8}{20}+\frac{20}{20}-\frac{15}{20}\)

\(\Leftrightarrow y=\frac{13}{20}\)

B) \(\frac{2}{3}\times y=\frac{4}{9}\times\frac{3}{8}\)

\(\Leftrightarrow\frac{2}{3}y=\frac{1}{6}\)

\(\Leftrightarrow2y=\frac{1}{2}\)

\(\Leftrightarrow y=\frac{1}{4}\)

CHO XIN

1+2+3+4+5+6+7+8+9+10=45

55 nha :>