a)\(\frac{12}{24}=\frac{1}{2}\)

b)\(-\frac{24}{45}=-\frac{4}{9}\)

Nhìu quá bn nhấn máy tính nhé!!!

ko bik dùng máy tính à

a)\(\dfrac{-3}{29}+\dfrac{16}{58}\)\(=\dfrac{-3}{29}+\dfrac{8}{29}=\dfrac{5}{29}\)

b) \(\dfrac{8}{40}+\dfrac{-36}{45}=\dfrac{1}{5}+\dfrac{-4}{5}=\dfrac{-3}{5}\)

c) \(\dfrac{-8}{18}+\dfrac{-15}{27}=\dfrac{-4}{9}+\dfrac{-5}{9}=\dfrac{-9}{9}=-1\)

a) \(\dfrac{-3}{29}+\dfrac{16}{58}=\dfrac{-3}{29}+\dfrac{8}{29}=\dfrac{-3+8}{29}=\dfrac{5}{29}\)

b) \(\dfrac{8}{40}+\dfrac{-36}{45}=\dfrac{1}{5}+\dfrac{-4}{5}=\dfrac{1+\left(-4\right)}{5}=\dfrac{-3}{5}\)

c) \(\dfrac{-8}{18}+\dfrac{-15}{27}=\dfrac{-4}{9}+\dfrac{-5}{9}=\dfrac{-4+\left(-5\right)}{9}=\dfrac{-9}{9}=-1\)

a) ; b) ; c) ; d) .

22/55=2/5

-63/81=-7/9

20/-140=-1/7

-25/-75=1/3

Tính các tổng dưới đây sau khi đã rút gọn phân số :

a)\(\dfrac{7}{21}\) + \(\dfrac{9}{-36}\) = \(\dfrac{7}{21}\)+\(\dfrac{-9}{36}\)=\(\dfrac{1}{3}\)+\(\dfrac{-1}{4}\)=\(\dfrac{4}{12}\)+\(\dfrac{-3}{12}\)=\(\dfrac{1}{12}\)

b) \(\dfrac{-12}{18}\)+\(\dfrac{-21}{35}\)=\(\dfrac{-2}{3}\)+\(\dfrac{-3}{5}\)=\(\dfrac{-10}{15}\)+\(\dfrac{-9}{15}\)=\(\dfrac{-19}{15}\)

c) \(\dfrac{-3}{21}\)+\(\dfrac{6}{42}\)=\(\dfrac{-1}{7}\)+\(\dfrac{1}{7}\)=0

d) \(\dfrac{-18}{24}\)+\(\dfrac{15}{-21}\)=\(\dfrac{-18}{24}\)+\(\dfrac{-15}{21}\)=\(\dfrac{-3}{4}\)+\(\dfrac{-5}{7}\)=\(\dfrac{-21}{28}\)+\(\dfrac{-20}{28}\)=\(\dfrac{-41}{28}\)

၁၁မန််ခခခ

`Answer:`

`a)` Ta có:

\(\frac{29-5}{54}=\frac{4}{9}\)

\(\frac{45-54}{33}=-\frac{3}{11}\)

Mẫu chung là `99`

\(\Rightarrow\frac{4}{9}=\frac{4.11}{9.11}=\frac{44}{99}\)

\(\Rightarrow\frac{-3}{11}=\frac{\left(-3\right).9}{11.9}=-\frac{27}{99}\)

`b)` Ta có:

\(\frac{18+14}{18}=\frac{16}{4}\)

\(\frac{26-50}{30}=-\frac{4}{5}\)

Mẫu chung là `45`

\(\Rightarrow\frac{16}{9}=\frac{16.5}{9.5}=\frac{80}{45}\)

\(\Rightarrow-\frac{4}{5}=\frac{\left(-4\right).9}{5.9}=-\frac{36}{45}\)

các bạn ơi thương mk một tí đi mà , chỉ một lần thôi 

bài 1

a, 1/4giowf          b,5/3 giờ

bài 3

-6/17=-6/17          -25/75=-1/3            42/-98=24/-49                 -12/27=-4/9

bài 2 dài lắm bạn ơi ,mình chỉ giúp đc vậy thôi

a) Rút gọn:

\(\dfrac{-1}{6};\dfrac{1}{5};\dfrac{-1}{2}\)

Quy đồng:

\(\dfrac{-5}{30};\dfrac{6}{30};\dfrac{-15}{30}\)

b) Rút gọn:

\(\dfrac{-3}{5};\dfrac{-5}{8};\dfrac{-4}{9}\)

Quy đồng:

\(\dfrac{-216}{360};\dfrac{-225}{360};\dfrac{-160}{360}\)

Rất tốt !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Tính máy tính nhé bạn

a)\(\frac{-15}{90}=\frac{-1}{6}\)=\(\frac{-5}{30}\);\(\frac{120}{600}=\frac{1}{5}\)=;\(\frac{-75}{150}=\frac{-1}{2}\)

Ta có: \(\frac{x}{42}=\frac{15}{21}=\frac{5}{7}\Rightarrow7x=42.5\)

                                              \(\Rightarrow7x=210\)

                                              \(\Rightarrow x=30\)

Tương tự: \(\frac{45}{y}=\frac{5}{7}\Rightarrow5y=45.7\)

                                      \(\Rightarrow5y=315\)

                                      \(\Rightarrow y=63\)

\(\frac{120}{z}=\frac{5}{7}\Rightarrow5z=120.7\)

                       \(\Rightarrow5z=840\)

                        \(\Rightarrow z=168\)

Vậy x = 30; y = 63 và z = 168

Ta có :  \(\frac{15}{21}=\frac{5}{7}\rightarrow\frac{x}{42}=\frac{45}{y}=\frac{120}{z}=\frac{5}{7}\)

Mà :  \(\frac{x}{42}=\frac{5}{7}\rightarrow x=\frac{42\cdot5}{7}=30\)

         \(\frac{45}{y}=\frac{5}{7}\rightarrow y=\frac{45\cdot7}{5}=63\)

         \(\frac{120}{z}=\frac{5}{7}\rightarrow z=\frac{120.7}{5}=168\)

a, \(\frac{7.25-49}{7.24+21}\)

\(=\frac{7.25-7.7}{7.24+7.3}=\frac{7\left(25-7\right)}{7\left(24+3\right)}=\frac{18}{27}=\frac{2}{3}\)

b, \(\frac{2.\left(-13\right).9.10}{\left(-3\right).4.\left(-5\right).26}=\frac{2.\left(-13\right).\left(-3\right).\left(-3\right).\left(-5\right).\left(-2\right)}{\left(-3\right).2.2.\left(-5\right).\left(-13\right).\left(-2\right)}\)

\(=\frac{-3}{2}\)

DỄ LẮM !

a) \(\frac{7\cdot25-49}{7\cdot24+21}=\frac{7\cdot25-7\cdot7}{7\cdot24+7\cdot3}=\frac{7\left(25-7\right)}{7\left(24+3\right)}\)

=\(\frac{18}{27}=\frac{2}{3}\)

b) \(\frac{2\cdot\left(-13\right)\cdot9\cdot10}{\left(-3\right)\cdot4\cdot\left(-5\right)\cdot26}=\frac{-1\cdot2\cdot13\cdot3\cdot3\cdot5\cdot2}{1\cdot3\cdot2\cdot2\cdot5\cdot13\cdot2}=-\frac{3}{2}\)

Chúc bn học tốt !