Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\dfrac{72}{90};\dfrac{48}{90};\dfrac{-135}{90};\dfrac{-900}{90};\dfrac{-70}{90}\)
Ta có: \(\dfrac{4}{5}=\dfrac{72}{90}\);\(\dfrac{8}{15}=\dfrac{48}{90}\);\(\dfrac{-3}{2}=\dfrac{-135}{90}\);\(\dfrac{-2}{10}=\dfrac{-18}{90}\);\(\dfrac{-7}{9}=\dfrac{-70}{90}\)
Bài 1:
a: 3/4=54/72
-1/9=-8/72
-5/8=-45/72
b: -1/7=-8/56
-1/-8=1/8=7/56
3/4=42/56
a: 3/4=54/72
-1/9=-8/72
-5/8=-45/72
b: -1/7=-8/56
1/8=7/56
3/4=42/56
c: 1/3=10/30
-1/5=-6/30
-1/10=-3/30
a)\(\dfrac{3}{4}=\dfrac{3.18}{4.18}=\dfrac{54}{72}\)
\(\dfrac{1}{-9}=\dfrac{-1}{9}=\dfrac{-1.8}{9.8}=\dfrac{-8}{72}\)
\(\dfrac{-5}{8}=\dfrac{-5.9}{8.9}=\dfrac{-45}{72}\)
b)\(\dfrac{1}{-7}=\dfrac{-1}{7}=\dfrac{-1.8}{7.8}=\dfrac{-8}{56}\)
\(\dfrac{-1}{-8}=\dfrac{1}{8}=\dfrac{1.7}{8.7}=\dfrac{7}{56}\)
\(\dfrac{3}{4}=\dfrac{3.14}{4.14}=\dfrac{42}{56}\)
c)\(\dfrac{1}{3}=\dfrac{1.10}{3.10}=\dfrac{10}{30}\)
\(\dfrac{-1}{5}=\dfrac{-1.6}{5.6}=\dfrac{-6}{30}\)
\(\dfrac{1}{-10}=\dfrac{-1}{10}=\dfrac{-1.3}{10.3}=\dfrac{-3}{30}\)
Ta có: \(\dfrac{5}{7} = \dfrac{{5.4}}{{7.4}} = \dfrac{{20}}{{28}}\) và \(\dfrac{{ - 3}}{4} = \dfrac{{ - 3.7}}{{4.7}} = \dfrac{{ - 21}}{{28}}\)
Như vậy, \(\dfrac{{20}}{{28}} + \dfrac{{ - 21}}{{28}} = \dfrac{{20 + \left( { - 21} \right)}}{{28}} = \dfrac{-1}{{28}}\)
\(\dfrac{5}{7}=\dfrac{75}{105};-\dfrac{3}{21}=-\dfrac{1}{7}=\dfrac{-15}{105};\dfrac{-8}{15}=\dfrac{-56}{105}\)
MSC : 360
`5/8 = (5xx45)/(8xx45)=225/360`
`7/20=(7xx18)/(20xx18)=126/360`
`-4/9=(-4xx40)/(9xx40)=-160/360`
=50/180;63/180;-80/180