Question

tìm x biết : 9+x   /    13-x = 5/6

Answer 1

\(\frac{9+x}{13-x}=\frac{5}{6}\)

\(\Leftrightarrow6\left(9+x\right)=5\left(13-x\right)\)

\(\Leftrightarrow54+6x=65-5x\)

\(\Leftrightarrow54-65=-5x-6x\)

\(\Leftrightarrow-11=-11x\)

\(\Leftrightarrow x=\frac{11}{11}\)

\(\Leftrightarrow x=1\)

Answer 2

\(\frac{9+x}{13-x}=\frac{5}{6}\)

\(\Rightarrow\text{ }6\left(9+x\right)=5\left(13-x\right)\)

\(\Rightarrow\text{ }54+6x=65-5x\)

\(\Rightarrow\text{ }54-65=-5x-6x\)

\(\Rightarrow\text{ }-11=-11x\)

\(\Rightarrow\text{ }x=-11\text{ : }\left(-11\right)\)

\(\Rightarrow\text{ }x=1\)