PD
1
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Các câu hỏi dưới đây có thể giống với câu hỏi trên
IB
13 tháng 10 2017
A, Câu này thì tớ chưa rõ lắm
B, 47 - [ ( 45 . 2^4 - 5^2 . 12 ) : 14] =
= 47 - [ ( 45. 16 - 25 . 12 ) : 14]
= 47 - [ ( 720 - 300 ) : 14]
= 47 - [ 420 : 14 ]
= 47 - 30
= 17
Chúc bạn học giỏi! :^
#Coffee
13 tháng 10 2017
A=50-[(50-2^3.5):2+3] B=47-[(45.2^4-5^2.12):14]
=50-[(50-40):2+3] =47-[(45.16-25.12):14]
=50-(10:2+3) =47-[(720-300):14]
=50-(5+3) =47-[420:14]
=50-8=42 =47-30=17
k tcik
K
24 tháng 3 2018
a) \(\dfrac{11}{21}+\dfrac{-4}{7}=\dfrac{11}{21}+\dfrac{-12}{21}=\dfrac{-1}{21}\)
b) \(\dfrac{5}{15}+\dfrac{14}{25}-\dfrac{12}{9}+\dfrac{2}{7}+\dfrac{11}{25}=\dfrac{1}{3}+\dfrac{14}{25}-\dfrac{4}{3}+\dfrac{2}{7}+\dfrac{11}{25}\)
\(=\left(\dfrac{1}{3}-\dfrac{4}{3}\right)+\left(\dfrac{14}{25}+\dfrac{11}{25}\right)+\dfrac{2}{7}=-1+1+\dfrac{2}{7}=\dfrac{2}{7}\)
c) \(\dfrac{2}{3}+\dfrac{5}{7}-\dfrac{3}{14}=\dfrac{28}{42}+\dfrac{30}{42}-\dfrac{9}{42}=\dfrac{49}{42}=\dfrac{7}{6}\)
d) \(\dfrac{2}{5}-\dfrac{3}{7}+\dfrac{9}{45}=\dfrac{2}{5}-\dfrac{3}{7}+\dfrac{1}{5}=\dfrac{14}{35}-\dfrac{15}{35}+\dfrac{7}{35}=\dfrac{6}{35}\)
e) \(\dfrac{21}{47}+\dfrac{9}{45}+\dfrac{26}{47}+\dfrac{45}{5}=\dfrac{21}{47}+\dfrac{1}{5}+\dfrac{26}{47}+\dfrac{45}{5}=\left(\dfrac{21}{47}+\dfrac{26}{47}\right)+\left(\dfrac{1}{5}+\dfrac{45}{5}\right)\)
\(=1+\dfrac{46}{5}=\dfrac{51}{5}\)
f) \(\dfrac{15}{12}-\dfrac{18}{13}+\dfrac{5}{13}-\dfrac{3}{12}=\left(\dfrac{15}{12}-\dfrac{3}{12}\right)+\left(-\dfrac{18}{13}+\dfrac{5}{13}\right)=1+\left(-1\right)=0\)
g) \(\dfrac{-8}{18}-\dfrac{15}{27}=\dfrac{-4}{9}-\dfrac{5}{9}=\dfrac{-9}{9}=-1\)
h)\(\dfrac{3}{7}+\dfrac{-5}{2}-\dfrac{3}{5}=\dfrac{30}{70}+\dfrac{-175}{70}-\dfrac{42}{70}=\dfrac{-187}{70}\)
i) \(\left(\dfrac{11}{12}:\dfrac{33}{16}\right).\dfrac{3}{5}=\dfrac{11}{12}.\dfrac{16}{33}.\dfrac{3}{5}=\dfrac{11.16.3}{12.33.5}=\dfrac{4}{15}\)
18 tháng 3 2018
a)\(\dfrac{2}{5}-\dfrac{3}{7}+\dfrac{9}{45}\\ =\dfrac{2}{5}-\dfrac{3}{7}+\dfrac{1}{5}\\ =\dfrac{14-15+1}{35}\\ =\dfrac{0}{35}=0\)
b)\(\dfrac{5}{15}+\dfrac{14}{25}-\dfrac{12}{9}+\dfrac{2}{7}+\dfrac{11}{25}\\ =\left(\dfrac{1}{3}-\dfrac{4}{3}\right)+\left(\dfrac{14}{25}+\dfrac{11}{25}\right)+\dfrac{2}{7}\\ =-1+1+\dfrac{2}{7}\\ =0+\dfrac{2}{7}=\dfrac{2}{7}\)
22 tháng 10 2019
a) \(47-\left[\left(45\cdot2^4-5^2\cdot12\right):14\right]\)
\(=47-\left[\left(45\cdot16-25\cdot12\right):14\right]\)
\(=47-\left[\left(720-300\right):14\right]\)
\(=47-\left[420:14\right]\)
\(=47-30=17\)
b) \(50-\left[\left(20-2^3\right):2+34\right]\)
\(=50-\left[\left(20-8\right):2+34\right]\)
\(=50-\left[12:2+34\right]\)
\(=50-\left[6+34\right]\)
\(=50-40=10\)
c) \(10^2-\left[60:\left(5^6:5^4-3\cdot5\right)\right]\)
\(=100-\left[60:\left(5^{6-4}-15\right)\right]\)
\(=100-\left[60:\left(5^2-15\right)\right]\)
\(=100-\left[60:\left(25-15\right)\right]\)
\(=100-\left[60:10\right]\)
\(=100-6=94\)
d) \(50-\left[\left(50-2^3\cdot5\right):2+3\right]\)
\(=50-\left[\left(50-8\cdot5\right):2+3\right]\)
\(=50-\left[\left(50-40\right):2+3\right]\)
\(=50-\left[10:2+3\right]\)
\(=50-\left[5+3\right]\)
\(=50-8=42\)
e) \(10-\left[\left(8^2-48\right)\cdot5+\left(2^3\cdot10+8\right)\right]:28\)
\(=10-\left[\left(64-48\right)\cdot5+\left(8\cdot10+8\right)\right]:28\)
\(=10-\left[16\cdot5+\left(80+8\right)\right]:28\)
\(=10-\left[80+88\right]:28\)
\(=10-168:28\)
\(=10-6=4\)
f) \(8697-\left[3^7:3^5+2\left(13-3\right)\right]\)
\(=8697-\left[3^{7-5}+2\cdot10\right]\)
\(=8697-\left[3^2+20\right]\)
\(=8697-\left[9+20\right]\)
\(=8697-29=8668\)
CHÚC BẠN HỌC TỐT!!!!!!!!!!!
2 tháng 4 2017
a) \(=\dfrac{-5}{12}.\dfrac{2}{7}+\dfrac{7}{12}.-\dfrac{3}{14}\)
\(=-\dfrac{5}{42}-\dfrac{1}{8}\)
= \(-\dfrac{41}{168}\)
b) \(=\dfrac{2.\left(-13\right).9.10}{\left(-3\right).4.\left(-5\right).26}\)
\(=\dfrac{1.1.3.\left(-2\right)}{\left(-1\right).2.1.\left(-2\right)}=\dfrac{3}{\left(-1\right).2}\)
\(=-\dfrac{3}{2}\)
16 tháng 5 2019
\(a.\frac{27.45+27.55}{2+4+6+...+14+16+18}=\frac{27.100}{\frac{\left(2+18\right).9}{2}}=30\)
\(b.\frac{26.108-26.12}{32-28+24-20+16-12+8-4}=\frac{26\left(108-12\right)}{\left(32-28\right).4}=\frac{26.96}{4.4}=156\)
\(c.\frac{27.4500+135.550.2}{2+4+6+...+14+16+18}=\frac{270.450+270.550}{\frac{\left(2+8\right).9}{2}}\)
\(d.\frac{48.700-24.45.20}{45-40+35-30+25-20+15-10+5}=\frac{48.700-48.450}{5.5}\)\(=\frac{48\left(700-450\right)}{25}=\frac{48.250}{25}=480\)
#ĐinhBa
13 tháng 4 2017
=>A=6/5-(19/7+26/5).
=>A=6/5-26/5-19/7.
=>A=-20/5-19/7.
=>A=-4+(-19/7)=-4 19/7 (đay là hỗn số).
B=47*45-47*15-47*45+47*15.
=>B=(47*45-47*45)+(47*15-47*15).
=>B=0+0.
=>B=0.
tk nha.
29 tháng 9 2018
1/a) 12 - x= 1-(-5)
12 - x = 6
x= 12-6
x=6
b)| x+4|= 12
x+4 = \(\pm\)12
*x+4=12
x=8
*x+4= -12
x=-16
2/Tìm n
\(n-5⋮n+2\)
=> \(n+2-7⋮n+2\)
mà \(n+2⋮n+2\)
=> 7\(⋮\)n+2
=> n+2 \(\varepsilon\)Ư(7)= {1;-1;7;-7}
| n+2 | 1 | -1 | 7 | -7 |
| n | -1 | -3 | 5 | -9 |
3/a)4.(-5)2 + 2.(-12)
= 2.2.(-5)2 + 2.(-12)
=2[2.25.(-12)]
=2.(-600)
=-1200
47 - [ ( 45 . 16 - 25 . 12 ) : 14 ]
47 - [ ( 720 - 300 ) : 14 ]
47 - [ 420 : 14 ]
47 - 30
17