2/5 + 3/10 - 1/2 giúp mình với
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`2x-15=-25`
`2x=-10`
`x=-5`
___________
`3/5<x/10<4/5`
`3/5=(3xx10)/(5xx10)=30/50`
`x/10=(5x)/(10xx5)=(5x)/50`
`4/5=(4xx10)/(5xx10)=40/50`
`=>30/50<(5x)/50<40/50`
`=>30<5x<40`
`=>x=7`
![](https://rs.olm.vn/images/avt/0.png?1311)
a) x - 1/2 = 3/5
x = 3/5 + 1/2
x = 11/10
b) x - 1/2 = -2/3
x = -2/3 + 1/2
x = -1/6
c) 2/5 - x = 0,25
x = 2/5 - 0,25
x = 2/5 - 1/4
x = 3/20
![](https://rs.olm.vn/images/avt/0.png?1311)
1+1-2-2-3-4-5-6-7-8-9+1+3+5+7+9+10
=-44+1+3+5+7+9+10
=-44+35
=-9
![](https://rs.olm.vn/images/avt/0.png?1311)
`1 5/27 + 7 /23 + 1/2 - 5/27 + 16/23`
` = 32/27 + 7/23 + 1/2 - 5/27 + 16/23 `
`= (32/27 - 5/27 ) + (7/23 + 16/23 ) + 1/2 `
`= 27/27 + 23/23 + 1/2 `
`= 1 + 1 + 1/2 `
`= 5/2`
` 6 1/5 - ( 2/3 . 9/10 - 7/5 )`
` = 31/5 - 2/3 . 9/10 + 7/5 `
`= ( 31/5 + 7/5 ) - ( 2/3 . 9/10 ) `
`= 38/5 - 3/5 `
`= 35/5`
`= 7`
`@ animephamdanhv.`
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* (-6 - 2) . (-6 + 2)
= -8 . -4
= 32
*(7 . 3 - 3) : (-6)
= 18 : (-6)
= -3
k cho mik nhe
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\Leftrightarrow2x\left(x+5\right)-3\left(x-2\right)=7x+1\)
\(\Leftrightarrow2x^2+10x-3x+6-7x-1=0\)
\(\Leftrightarrow2x^2+5=0\)(vô lý)
ĐKXĐ:\(\left\{{}\begin{matrix}x\ne2\\x\ne-5\end{matrix}\right.\)
\(\dfrac{2x}{x-2}-\dfrac{3}{x+5}=\dfrac{7x+1}{x^2+3x-10}\\ \Leftrightarrow\dfrac{2x\left(x+5\right)}{\left(x+5\right)\left(x-2\right)}-\dfrac{3\left(x-2\right)}{\left(x+5\right)\left(x-2\right)}=\dfrac{7x+1}{x^2-2x+5x-10}\\ \Leftrightarrow\dfrac{2x^2+10x}{\left(x+5\right)\left(x-2\right)}-\dfrac{3x-6}{\left(x+5\right)\left(x-2\right)}=\dfrac{7x+1}{x\left(x-2\right)+5\left(x-2\right)}\\ \Leftrightarrow\dfrac{2x^2+10x}{\left(x+5\right)\left(x-2\right)}-\dfrac{3x-6}{\left(x+5\right)\left(x-2\right)}-\dfrac{7x+1}{\left(x+5\right)\left(x-2\right)}=0\)
\(\Leftrightarrow\dfrac{2x^2+10x-3x+6-7x-1}{\left(x+5\right)\left(x-2\right)}=0\\ \Leftrightarrow\dfrac{2x^2+5}{\left(x+5\right)\left(x-2\right)}=0\\ \Rightarrow2x^2+5=0\left(vô.lí\right)\)
Vậy pt vô nghiệm
![](https://rs.olm.vn/images/avt/0.png?1311)
a)2/5+3/4
=23/20
b)2/5 + 3/10-1/2
=7/10-1/2
=1/5
c)8/11+8/33x3/4
=8/11 + 2/11
=10/11
tick cho mik nha mik cháy đen túi r
hok tốt
\(=\dfrac{4}{10}+\dfrac{3}{10}-\dfrac{5}{10}=\dfrac{2}{10}=\dfrac{1}{5}\)
\(\dfrac{2}{5}+\dfrac{3}{10}-\dfrac{1}{2}=\dfrac{4}{10}+\dfrac{3}{10}-\dfrac{5}{10}=\dfrac{4+3-5}{10}=\dfrac{2}{10}=\dfrac{1}{5}\)