Question

Tìm x biết:

Answer 1

\(\dfrac{x+8}{12}+\dfrac{x+9}{11}+\dfrac{x+10}{10}+3=0\)

\(\Leftrightarrow\left(\dfrac{x+8}{12}+1\right)+\left(\dfrac{x+9}{11}+1\right)+\left(\dfrac{x+10}{10}+1\right)=0\)

\(\Leftrightarrow\dfrac{x+20}{12}+\dfrac{x+20}{11}+\dfrac{x+20}{10}=0\)

\(\Leftrightarrow\left(x+20\right)\left(\dfrac{1}{12}+\dfrac{1}{11}+\dfrac{1}{10}\right)=0\)

\(\Leftrightarrow x+20=0\)

\(\Leftrightarrow x=-20\)

 

Answer 2

`(x + 8)/12 + (x + 9)/11 + (x + 10)/10 + 3 = 0`

`<=> ((x + 8)/12 + 1) + ((x + 9)/11 + 1) + (x + 10)/10 + 1) = 0`

`<=> (x + 20)/12 + (x + 20)/11 + (x + 20)/10 = 0`

`<=> (x + 20) . (1/12 + 1/11 + 1/10) = 0`

`<=> x + 20 = 0`

`=> x = -20`

Vậy `x = -20`