\(\Leftrightarrow\)\(\dfrac{x}{7}-\dfrac{20}{7}+\dfrac{x}{33}-\dfrac{46}{33}+\dfrac{x}{8}-\dfrac{5}{8}+\dfrac{x}{19}+\dfrac{6}{19}=0\)
\(\dfrac{5016x}{35112}+\dfrac{1064x}{35112}+\dfrac{4389x}{35112}+\dfrac{1848x}{35112}=\dfrac{100320}{35112}+\dfrac{48994}{35112}-\dfrac{21945}{35112}+\dfrac{11088}{35112}\)
\(\dfrac{12317x}{35112}=\dfrac{160121}{35112}\)
\(12317x=160121\)
\(x=13\)
Làm cách này nhưng tớ thấy nó vẫn không tiến triển gì, thôi, qua cái này:
\(\dfrac{x-20}{7}+\dfrac{x-46}{33}+\dfrac{x-5}{8}+\dfrac{x+6}{19}=0\)
\(\dfrac{5016\left(x-20\right)+1064\left(x-46\right)+4389\left(x-5\right)+1848\left(x+6\right)}{35112}=0\)
\(5016x+1064x+4389x+1848x=100320+48944+21945-11088\)
\(12317x=160121\)
\(x=13\)
\(\Leftrightarrow\frac{x-20}{7}+1+\frac{x-46}{33}+1+\frac{x-5}{8}-1+\frac{x+6}{19}-1=0\)
\(\Leftrightarrow\frac{x-13}{7}+\frac{x-13}{33}+\frac{x-13}{8}+\frac{x-13}{19}=0\)
\(\Leftrightarrow\left(x-13\right)\left(\frac{1}{7}+\frac{1}{33}+\frac{1}{8}+\frac{1}{19}\right)=0\)
\(\Leftrightarrow x-13=0\)
\(\Leftrightarrow x=13\)
Ta có *chú ý: mk thêm bớt chỗ 1 nha\(\left(\dfrac{x-20}{7}+1\right)+\left(\dfrac{x-46}{33}+1\right)+\left(\dfrac{x-5}{8}-1\right)+\left(\dfrac{x+6}{19}-1\right)=0\)\(\Leftrightarrow\dfrac{x-20+7}{7}+\dfrac{x-46+33}{33}+\dfrac{x-5-8}{8}+\dfrac{x+6-19}{19}=0\)\(\Leftrightarrow\dfrac{x-13}{7}+\dfrac{x-13}{33}+\dfrac{x-13}{8}+\dfrac{x-13}{19}=0\)
\(\Leftrightarrow\left(x-13\right)\left(\dfrac{1}{7}+\dfrac{1}{33}+\dfrac{1}{8}+\dfrac{1}{19}\right)=0\)
\(\Rightarrow x-13=0\) (vì \(\dfrac{1}{7}+\dfrac{1}{33}+\dfrac{1}{8}+\dfrac{1}{19}\ne0\))
\(\Leftrightarrow x=13\)
Vậy tập nghiệm của pt là S=\(\left\{13\right\}\)