![](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)
a) \(\frac{4}{5}=\frac{28}{35}\)
b) \(\frac{12}{15}=\frac{72}{90}\)
c) \(\frac{125}{300}=\frac{5}{12}\)
d) \(\frac{6}{9}=\frac{36}{54}\)
/HT\
a) \(\frac{4}{5}=\frac{28}{35}\) \(\text{X}=28\)
b) \(\frac{12}{15}=\frac{72}{90}\) \(\text{X}=90\)
c) \(\frac{125}{300}=\frac{5}{12}\) \(\text{X}=12\)
d) \(\frac{6}{9}=\frac{36}{54}\) \(\text{X}=6\)
![](https://rs.olm.vn/images/avt/0.png?1311)
175 x 54 + 525 x 15 + 175
= 175 x 54 + 175 x (3 x 15) + 175
= 175 x 54 + 175 x 45 + 175
= 175 x (54 + 45 + 1) = 175 x 100 = 17500
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
54 x 275 + 825 x 15 + 275
=14850 + 825 x 15 + 275
=14850 + 12375+275
=14850 + 12650
=27500
477x1998-1998x427
=1998x(477-427)
=1998x50
=99900
1985:2+15:2
=(1985+15):2
=2000:2
=1000
40x113x25-20x112x50
=(40x25)x113-(20x50)x112
=1000x113-1000-112
=1000x(113-112)
=1000x1
=1000
câu 1, ??????????????
câu 2, [477-427], +[1998-1998]=50+0=50
câu 3,[1985+15]:2=2000:2=1000
câu 4, ??????????
chú thích ? là ko có cách tính nhanh
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,123\times54+27\times123-12\times123+123\times31\)
\(=123\times\left(54+27-12+31\right)\)
\(=123\times100\)
\(=12300\)
\(b,\dfrac{121}{27}\times\dfrac{54}{11}< n< \dfrac{100}{21}:\dfrac{25}{126}\)
\(22< n< \dfrac{100}{21}\times\dfrac{126}{25}\)
\(22< n< 24\)
Vì \(23>22\) và \(23< 24\) nên \(n=23\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a123x54+27x123-12x123+123x31
=123:54+27:123-12:123+123:31
=6642+27:123-12:123+123:31
=6642+3321-12:123+123:31
=6642+3321-1476+123:31
=6642+3321-1476+3813
=12300
b,121/27x54/11<n>100/21:25/126
=22<n>24
n=23
![](https://rs.olm.vn/images/avt/0.png?1311)
ĐK: x khác 0
54:x + 36:x = 9
=> 90 : x = 9
=> x = 10 (TM)
Vậy x = 10
54 - x = 15
x = 54 - 15
x = 39
54 - x = 15
x = 54 - 15
x = 39