Question

Answer 1

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

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

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

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

\(=>x+20=0=>x=-20\)

Answer 2

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

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

\(\Leftrightarrow x+20=0\)

hay x=-20