![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{6}{18}+\frac{-14}{21}=\frac{1}{3}+\frac{-2}{3}=\frac{-1}{3}\); ;
\(\frac{6}{13}+\frac{-14}{39}=\frac{18}{39}+\frac{-14}{39}=\frac{4}{39}\);
\(\frac{-3}{21}+\frac{6}{42}=\frac{-1}{7}+\frac{1}{7}=0\);
\(\frac{7}{21}+\frac{9}{-36}=\frac{1}{3}+\frac{-1}{4}=\frac{4}{12}+\frac{-3}{12}=\frac{1}{12}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
b) = 27.(58+42)
= 27.100=2700
d) =18.(68+39-7)
=18.100=1800
![](https://rs.olm.vn/images/avt/0.png?1311)
a, UCLN(42;58) = 2
b, UCLN(18;30;42) = 6
c, UCLN(26;39;48) = 1
d, UCLN(85;161) = 1
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\left(39\times42-37\times42\right):42\)
\(=\left[42\left(39-37\right)\right]:42\)
\(=42.2:42=84:42\)
\(=2\)
![](https://rs.olm.vn/images/avt/0.png?1311)
=a+(-28+18)-(42+18+a)
=a+(-10)-(60+a)
=a+(-10)-60-a
=(-10)-60
=(-70)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
42 . x = 39 . 42 - 37. 42
=> 42x=42.(39-37)
=> 42x=42.2
=> x=2