
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.




(19 phút 18 giây+ 5 Phút 12 giây) x 7
= 24 phút 30 giây x 7
= 18 phút 30 giây
hok tốt


a, 2015 - 2 × X = 101
2 x X = 2015 - 101
2 x X = 1914
X = 1914 : 2
X = 957
1a. 2015 - 2 x X = 101
2 x X = 2015 - 101
X = 1914 : 2
X = 957
b. 7 - (11 + X - 13) : \(2\frac{2}{3}\)= 2
(11 + X - 13) : \(2\frac{2}{3}\) = 7 - 2
11 + X - 13 = 5 x \(2\frac{2}{3}\)
11 + X = \(\frac{40}{3}\)+ 13
X = \(\frac{79}{3}\)- 11
X = \(\frac{46}{3}\)
c. 2012 - 5 x X = 17
5 x X = 2012 - 17
X = 1995 : 5
X = 399
d. \(5\frac{3}{4}\)+ (X - 2) x \(\frac{1}{3}\)= \(17\frac{3}{4}\)
(X - 2) x \(\frac{1}{3}\) = \(17\frac{3}{4}\)- \(5\frac{3}{4}\)
X - 2 = 12 : \(\frac{1}{3}\)
X = 36 + 2
X = 38
e. 12 x (X - 5) + 73 = 20
12 x (X - 5) = 20 - 73
X - 5 = -53 : 12
X = \(\frac{-53}{12}\)+ 5
X = \(\frac{7}{12}\)

a) (x + 73) - 26 = 76
x + 73 = 76 + 26
x + 73 = 102
x = 102-73
x = 29
b) 45-(c + 9) = 6
c + 9 = 6 + 45
c + 9 =51
c =51 - 9
c = 42
c) 89 - (73 - x)= 20
73 - x = 89 - 20
73 - x = 69
x = 73 - 69
x = 4
d) (x + 7) - 25 = 13
x + 7 = 13 + 25
x + 7 = 38
x = 38 - 7
x = 31
e) 198 - (x + 4) = 120
x + 4 = 198 - 120
x + 4 = 68
x = 68 - 4
x = 64

1a)\(\dfrac{14}{3}-\dfrac{11}{4}+\dfrac{80}{11}\)
= \(\dfrac{23}{12}\) + \(\dfrac{80}{11}\)
= \(\dfrac{1213}{132}\)
b \(\dfrac{4}{5}\times\dfrac{15}{16}+\dfrac{5}{2}:\dfrac{20}{9}\)
= \(\dfrac{3}{4}+\dfrac{5}{2}\times\dfrac{9}{20}\)
= \(\dfrac{3}{4}+\dfrac{9}{8}\)
= \(\dfrac{15}{8}\)
b 204 x 307 - 148004 : 209
= 62628 - 708,15311
=61919,846889

12 . ( y - 6 ) = 4 . y + 12
12y - 72 = 4y + 12
12y - 4y = 12 + 72
8y = 84
y = 12
Vậy y = 12
12(y-6)=4y+12
<=> 12y-72=4y+12
<=>12y-4y=12+72
<=>8y=84
<=>y=10.5

\(B=\frac{10}{18}\times\frac{22}{30}\times\frac{36}{44}\times...\times\frac{200}{209}=\frac{1\times10}{2\times9}\times\frac{2\times11}{3\times10}\times\frac{3\times12}{4\times11}\times...\times\frac{10\times20}{11\times19}\)
\(=\frac{1\times10\times2\times11\times3\times12\times...\times10\times20}{2\times9\times3\times10\times4\times11\times...\times11\times19}=\frac{\left(1\times2\times3\times...\times10\right)\times\left(10\times11\times12\times...\times20\right)}{\left(2\times3\times4\times...\times11\right)\times\left(9\times10\times11\times...\times19\right)}\)
\(=\frac{1\times20}{11\times9}=\frac{20}{99}\)
Sửa đề \(C=\left(1-\frac{1}{4}\right)\times\left(1-\frac{1}{9}\right)\times\left(1-\frac{1}{16}\right)\times...\times\left(1-\frac{1}{100}\right)\)
\(=\frac{3}{4}\times\frac{8}{9}\times\frac{15}{16}\times...\times\frac{99}{100}=\frac{3\times8\times15\times...\times99}{4\times9\times16\times...\times100}=\frac{1\times3\times2\times4\times3\times5\times...\times9\times11}{2\times2\times3\times3\times4\times4\times...\times10\times10}\)
\(=\frac{\left(1\times2\times3\times....\times9\right)\times\left(3\times4\times5\times...\times11\right)}{\left(2\times3\times4\times...\times10\right)\times\left(2\times3\times4\times...\times10\right)}=\frac{1\times11}{10\times2}=\frac{11}{20}\)
ta có :
\(12\times y:4+209-73=0\)
hay \(3\times y+136=0\)
hay ta có \(3\times y=-136\text{ vậy }y=-\frac{136}{3}\)