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a)\(3:\left(2x+1\right)=72-69\)
\(3:\left(2x+1\right)=3\)
\(2x+1=3:3\)
\(2x+1=1\)
\(2x=1-1\)
\(2x=0\)
\(x=0:2\)
\(x=0\)
các bài còn lại giống như câu a nha nếu ko biết thì comment lại minhf sẽ giải cho . Nhớ k cho mình nha
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Bài 2:
a, \(\dfrac{5}{23}\) \(\times\) \(\dfrac{17}{26}\) + \(\dfrac{5}{23}\) \(\times\) \(\dfrac{9}{26}\)
= \(\dfrac{5}{23}\) \(\times\) ( \(\dfrac{17}{26}\) + \(\dfrac{9}{26}\))
= \(\dfrac{5}{23}\) \(\times\) \(\dfrac{26}{26}\)
= \(\dfrac{5}{23}\)
b, \(\dfrac{3}{4}\) \(\times\) \(\dfrac{7}{9}\) + \(\dfrac{7}{4}\) \(\times\) \(\dfrac{3}{9}\)
= \(\dfrac{7}{12}\) + \(\dfrac{7}{12}\)
= \(\dfrac{14}{12}\)
= \(\dfrac{7}{6}\)
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Bài 1: Tính
a) =1\(\frac{49}{60}\)
b) =2\(\frac{13}{30}\)
Bài 2: Tìm x
a) =4\(\frac{1}{21}\)
Riêng câu b) thì mk nghĩ là bạn viết lộn vì mk thấy cái chỗ xx3/4 là mk ko hiểu rồi
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=>1/16: [3/10.x+5/2] = 20 => 3/10.x +5/2 = 1/320 => 3/10.x = -799/320 => x = -799/96
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a) Số các số hạng :
[(x + 16) - (x + 1)] + 1 = 16 (số hạng)
Tổng trên là :
[(x + 16) + (x + 1)] x 16 : 2 = (2x + 17) x 16 : 2 = 154
=> (2x + 17) x 16 = 208
=> 2x + 7 = 13
=> 2x = 20
=> x = 10
a) ( x + 1 ) + ( x + 2 ) + ( x + 3 ) + .... + ( x + 16 ) = 154
=> x + 1 + x + 2 + x + 3 + ... + x + 16 = 154
=> ( x + x + x + ... + x ) + ( 1 + 2 + 3 + ... + 16 ) = 154
=> 16x + 136 = 154
=> x = ( 154 - 136 ) : 16
=> x = 9/8
b) ( x + 1 ) + ( x + 3 ) + ( x + 5 ) + ... + ( x + 19 ) = 245
=> x + 1 + x + 3 + x + 5 + ... + x + 19 = 245
=> ( x + x + x + ... + x ) + ( 1 + 3 + 5 + ... + 19 ) = 245
=> 10x + 100 = 245
=> x = ( 245 - 100 ) : 10
=> x = 9/2
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`a)4/5+5 1/2 xx (4,5-2)+7/10`
`=4/5+11/2*2,5+7/10`
`=0,8+2,2+0,7`
`=3+0,7=3,7`
`b)125%xx 17/4:(1 5/16-0,5)+2008`
`=1,25xx4,25:13/16+2008`
`=85/13+2008`
`=2014 7/13`
`c)5/11+(16/11+1)`
`=5/11+1+5/11+1`
`=2+10/11=32/11`
`d)3/17+11/4+5/8+14/17+3/8`
`=3/17+14/17+5/8+3/8+11/4`
`=1+1+11/4`
`=19/4`
a)
\(\dfrac{4}{5}+5\dfrac{1}{2}x\left(4,5-2\right)=\dfrac{7}{10}\)
<=> \(\dfrac{11}{2}x\times2,5=\dfrac{7}{10}-\dfrac{4}{5}=\dfrac{-1}{10}\)
<=> \(\dfrac{55}{4}x=\dfrac{-1}{10}< =>x=\dfrac{-2}{275}\)
b) \(125\%\times\dfrac{17}{4}:\left(1\dfrac{5}{16}-0,5\right)+2008\)
= \(\dfrac{85}{16}:\left(\dfrac{21}{16}-\dfrac{1}{2}\right)+2008=\dfrac{85}{16}:\dfrac{13}{16}+2008=\dfrac{26189}{13}\)
c) \(\dfrac{5}{11}+\left(\dfrac{16}{11}+1\right)\)
= \(\dfrac{21}{11}+1=\dfrac{32}{11}\)
d) \(\left(\dfrac{3}{17}+\dfrac{14}{17}\right)+\left(\dfrac{5}{8}+\dfrac{3}{8}\right)+\dfrac{11}{4}\)
= 1 + 1 + \(\dfrac{11}{4}\) = \(\dfrac{19}{4}\)
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1 * 2 * 3 * 4 * 5 * 6 * 6 * 7 * 8 * 9 * 10 * 11 * 12 * 13 * 14 * 15 * 16 * 17 * 18 * 0 * 19 * 20
= 0 nha
Bởi vì trong dãy số nhân này có nhân với số 0
Chúc bạn học tốt
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Bài 1:
a) \(2\)\(\dfrac{2}{3}\)\(=\dfrac{8}{3}\)
b) \(1\)\(\dfrac{5}{7}=\dfrac{12}{7}\)
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1) x:0,5+3.x-10=5
x: 0,5 + 3.x=5+10
=> x:1/2 + 3.x=15
=>x.2/1 + 3x = 15
x(2+3)= 15
x.5=15
=> x = 15:5
=> x=3