Question

tìm x

a, \(\frac{5}{6}=\frac{-1}{x}\)

b,\(\frac{-3}{7}=\frac{x}{14}\)

c,\(\frac{x+1}{4}=\frac{-3}{2}\)

d,\(\frac{2x-3}{5}=\frac{-6}{7}\)

e,\(\frac{3-5x}{4}=\frac{5}{6}\)

f,\(\frac{12}{x}=\frac{-6}{5}\)

Answer 1

a) \(\frac{5}{6}=\frac{-1}{x}\) \(\Leftrightarrow\) 5x = -1 . 6 \(\Leftrightarrow\) x = \(\frac{-6}{5}\) = -1,2

b)\(\frac{-3}{7}=\frac{x}{14}\Leftrightarrow\) -3 . 14 = 7x \(\Leftrightarrow\) x = \(\frac{-3.14}{7}\) = -6

c)\(\frac{x+1}{4}=\frac{-3}{2}\) \(\Leftrightarrow\) 2(x+1) = -3.4\(\Leftrightarrow\) \(x+1=\frac{-3.4}{2}\) = -6 \(\Leftrightarrow\) x = -6 - 1= -7

d) \(\frac{2x-3}{5}=\frac{-6}{7}\) \(\Leftrightarrow\) 2x - 3 = \(\frac{-6.5}{7}\) = \(\frac{-30}{7}\) \(\Leftrightarrow\) 2x = \(\frac{-30}{7}+3\) = \(\frac{-9}{7}\)

\(\Leftrightarrow\) x = \(\frac{-9}{7}:2\) = \(\frac{-9}{14}\)

e) \(\frac{3-5x}{4}=\frac{5}{6}\) \(\Leftrightarrow\) 3-5x = \(\frac{5.4}{6}\) = \(\frac{10}{3}\) \(\Leftrightarrow\) 5x = 3-\(\frac{10}{3}\) = \(\frac{-1}{3}\) \(\Leftrightarrow\) x = \(\frac{-1}{15}\)

f)\(\frac{12}{x}=\frac{-6}{5}\) \(\Leftrightarrow\) x = \(\frac{12.5}{-6}\) = -10