Question

tìm x biết ( 0,25 - 30 % . x ).1/3 - 1/4 = -5  1 phần 6

Answer 1

\(\left(0,25-30\%.x\right).\frac{1}{3}-\frac{1}{4}=-5\frac{1}{6}\)

\(< =>\left(\frac{1}{4}-\frac{3x}{10}\right).\frac{1}{3}-\frac{1}{4}=-\frac{30}{6}\)

\(< =>\left(\frac{1}{4}-\frac{3x}{10}\right).\frac{1}{3}=-5+\frac{1}{4}=-\frac{19}{4}\)

\(< =>\frac{1}{4}-\frac{3x}{10}=\frac{-19}{4}.\frac{3}{1}=-\frac{57}{4}\)

\(< =>\frac{-3x}{10}=\frac{-57}{4}-\frac{1}{4}=-\frac{58}{4}\)

\(< =>-12x=-580\)

\(< =>12x=580< =>x=\frac{580}{12}=\frac{145}{3}\)

Answer 2

\(\left(0,25-30\%x\right).\frac{1}{3}-\frac{1}{4}=-5\frac{1}{6}\)

\(\left(\frac{1}{4}-\frac{3}{10}x\right)\frac{1}{3}-\frac{1}{4}=\frac{-31}{6}\)

\(\frac{1}{4}-\frac{3}{10}x=\left(\frac{-31}{6}+\frac{1}{4}\right)\div\frac{1}{3}\)

\(\frac{1}{4}-\frac{3}{10}x=\frac{-59}{4}\)

\(\frac{3}{10}x=\frac{1}{4}-\frac{-59}{4}\)

\(\frac{3}{10}x=15\Leftrightarrow x=50\)