Tìm x :
a) 1,8 : (2,7 – $\frac{x – 1}{3}$ ) = 9
b) $\frac{4}{5}$ : 3 × ` x ` = 20%
Tìm x : a) 1,8 : (2,7 – $\frac{x – 1}{3}$ ) = 9 b) $\frac{4}{5}$ : 3 × ` x ` = 20%
By Natalia
By Natalia
Tìm x :
a) 1,8 : (2,7 – $\frac{x – 1}{3}$ ) = 9
b) $\frac{4}{5}$ : 3 × ` x ` = 20%
`1,8:(2,7-(x-1)/(3))=9`
`<=>` `1,8:((8,1-x+1)/(3))=9`
`<=>` `1,8.(3)/(9,1+x)=9`
`<=>` `(5,4)/(9,1+x)=9`
`<=>` `5,4=9(9,1+x)`
`<=>` `5,4=81,9+9x`
`<=>` `76,5=9x`
`<=>` `x=8,5`
Vậy `x=8,5`
`1,8 : (2,7 – (x-1)/3) = 9`
`=> 2,7 – (x-1)/3 = 1,8 : 9`
`=> 2,7 – (x-1)/3 = 0,2`
`=> (x-1)/3 = 2,7 – 0,2`
`=> (x-1)/3 = 2,5`
`=> (x-1)/3 = (7,5)/3`
`=> x-1 = 7,5`
`=> x = 7,5 + 1`
`=> x = 8,5`
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