a) x/10-(x/30+2x/45)=4/5 b) 5(2x-1)/18+x+3/12=7x+3/6-2(3-x)/9

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1. .

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2. Lời giải :

   `a) x/10-(x/30+(2x)/45)=4/5`

   `⇔x/10-x/30-(2x)/45=4/5`

   `⇔(9x)/90-(3x)/90-(4x)/90=72/90`

   `⇔9x-3x-4x=72`

   `⇔2x=72`

   `⇔x=36`

   `b) 5(2x-1)/18+x+3/12=7x+3/6-2(3-x)/9`

   `⇔10(2x−1)+3(x+3)=6(7x+3)−8(3−x)`

   `⇔20x−10+3x+9=42x+18−24+8x`

   `⇔23x−1=50x−6`

   `⇔27x=5`

   `⇔x=5/27`

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