Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Bài 2:
a: 2/5=14/35
3/7=15/35
b: -3/4=-9/12
-7/-12=7/12
c: 5/9=60/108
-11/-12=11/12=99/108
d: -4/7=-36/63
8/9=56/63
-10/21=-30/63
Bài 2:
a: 2/5=14/35
3/7=15/35
b: -3/4=-9/12
-7/-12=7/12
c: 5/9=60/108
-11/-12=11/12=99/108
d: -4/7=-36/63
8/9=56/63
-10/21=-30/63
a)\(\dfrac{-36}{63};\dfrac{56}{63};\dfrac{-30}{63}\)
b)\(\dfrac{110}{264};\dfrac{21}{264}\)
a) -12/18=-420/630
-21/35=-378/630
-420/630+378/630=-42/630=-1/15
b) 27/5=81/15
8/3 = 40/15
81/15+40/15=121/15
c) 11/4=77/28
9/7=36/28
77/28+36/28=113/28
a) -12/18=-420/630
-21/35=-378/630
-420/630+378/630=-42/630=-1/15
b) 27/5=81/15
8/3 = 40/15
81/15+40/15=121/15
c) 11/4=77/28
9/7=36/28
77/28+36/28=113/28
1. Rút gọn phân số
a) \(\dfrac{-12}{21}\) = \(\dfrac{-12:3}{21:3}\) = \(\dfrac{-4}{7}\)
b) \(\dfrac{-63}{81}\) = \(\dfrac{-63:9}{81:9}\) = \(\dfrac{-7}{9}\)
2. Quy đồng mẫu số
\(\dfrac{-6}{5}\) \(\dfrac{8}{-4}\)
⇒ \(\dfrac{-6}{5}\) = \(\dfrac{-8}{4}\) MSC: 20
\(\dfrac{-6}{5}\) = \(\dfrac{-24}{20}\)
\(\dfrac{-8}{4}\) = \(\dfrac{-40}{20}\)
3. So sánh phân số
\(\dfrac{6}{7}\) và \(\dfrac{11}{10}\) MSC: 70
\(\dfrac{6}{7}\) = \(\dfrac{60}{70}\)
\(\dfrac{11}{10}\) = \(\dfrac{77}{70}\)
Vì \(\dfrac{60}{70}\) < \(\dfrac{77}{70}\) nên \(\dfrac{6}{7}\) < \(\dfrac{11}{10}\)
4. Cộng hai phân số
a) \(\dfrac{3}{4}\) + \(\dfrac{-7}{6}\) MSC: 12
\(\dfrac{3}{4}\) = \(\dfrac{9}{12}\)
\(\dfrac{-7}{6}\) = \(\dfrac{-14}{12}\)
\(\dfrac{9+\left(-4\right)}{12}\) = \(\dfrac{-5}{12}\)