Qui đồng rồi khử mẫu, ta được:
\(4x+12.\left(27-x\right)=15x+5.\left(27-x\right)\)
\(\Leftrightarrow4x+324-12x=15x+135-5x\)
\(\Leftrightarrow4x-12x-15x+5x=135-324\)
\(\Leftrightarrow-18x=-189\Leftrightarrow x=\frac{21}{2}=10,5\)
Vậy x = 10,5
\(\frac{x}{15}+\frac{27-x}{5}=\frac{x}{4}+\frac{27-x}{12}\)
\(\frac{x}{15}+\frac{3\left(27-x\right)}{15}=\frac{3x}{12}+\frac{27-x}{12}\)
\(\frac{x}{15}+\frac{81-3x}{15}=\frac{3x}{12}+\frac{27-x}{12}\)
\(\frac{x+81-3x}{15}=\frac{3x+27-x}{12}\)
\(\frac{-2x+81}{15}=\frac{2x+27}{12}\)
\(12\left(-2x+81\right)=15\left(2x+27\right)\)
\(-24x+972=30x+405\)
\(972-405=30x+24x\)
\(567=54x\)
\(x=567:54\)
\(x=10,5\)
\(\frac{x}{15}+\frac{27-x}{5}=\frac{x}{4}+\frac{27-x}{12}\)
\(\Leftrightarrow\frac{4x}{60}+\frac{12\left(27-x\right)}{5}=\frac{15x}{60}+\frac{5\left(27-x\right)}{12}\)
\(\Leftrightarrow4x+324-12x=15x+135-5x\)
\(\Leftrightarrow4x-12x-15x+5x=135-324\)
\(\Leftrightarrow-18x=-189\)
\(x=\frac{-189}{-18}=\frac{21}{2}=10,5\)
\(\frac{x}{15}+\frac{27-x}{5}=\frac{x}{4}+\frac{27-x}{12}\)
\(=>\frac{x}{15}+\frac{81-3x}{15}=\frac{3x}{12}+\frac{27-x}{12}\)
\(=>\frac{x+\left(81-3x\right)}{15}=\frac{3x+\left(27-x\right)}{12}\)
\(=>\frac{81-2x}{15}=\frac{27+2x}{12}\)
\(=>\frac{12.\left(81-2x\right)}{180}=\frac{15.\left(27+2x\right)}{180}\)
=> 12 . (81 - 2x) = 15 . (27 + 2x) (Vì 180 \(\ne\)0)
=> 972 - 24x = 405 + 30x
=> -24x - 30x = 405 - 972
=> -54x = -567
=> x = \(\frac{21}{2}\)
Vậy x = \(\frac{21}{2}\)
=
\(\frac{x}{15}+\frac{27-x}{5}=\frac{x}{4}+\frac{27-x}{12}\)
\(\Leftrightarrow\frac{4x}{60}+\frac{12\left(27-x\right)}{5}=\frac{15x}{60}+\frac{5\left(27-x\right)}{12}\)
\(\Leftrightarrow4x+324-12x=15x+135-5x\)
\(\Leftrightarrow4x-12x-15x+5x=135-324\)
\(\Leftrightarrow-18x=-189\)
\(x=\frac{-189}{-18}=\frac{21}{2}=10,5\)
