Question

7/8x - 5(x -9) = 20x + 1,5/6

giúp mk cái☺

Answer 1

<=>(7/8-5-20)x=3/12-45

<=>(7-40-160)x=2-90

-193x=-88

x=88/193

Answer 2

\(\dfrac{7}{8x}-5\left(x-9\right)=20x+\dfrac{1,5}{6}\)

\(\Leftrightarrow7-8x.5\left(x-9\right)=120x+1,5\)

\(\Leftrightarrow7-40x^2+360x=120x+1,5\)

\(\Leftrightarrow-40x^2+360x-120x=7+1,5\)

\(\Leftrightarrow-40x^2+240x=8,5\)

\(\Leftrightarrow40x\left(-x-6\right)=8,5\)

\(\Leftrightarrow\left[{}\begin{matrix}40x=8,5\\-x-6=8,5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{17}{80}\\x=-\dfrac{29}{2}\end{matrix}\right.\)

S\(=\left\{\dfrac{17}{80},\dfrac{-29}{2}\right\}\)