Question

Tìm số tự nhiên x sao cho:

\(\frac{12+x}{43-x}=\frac{2}{3}\)

Giúp mk nhé 

Answer 1

\(\frac{12+x}{43-x}=\frac{2}{3}\)\(\Rightarrow3\left(12+x\right)=2\left(43-x\right)\)

\(\Rightarrow36+3x=86-2x\)

\(\Rightarrow36+3x-86+2x=0\)

\(\Rightarrow5x=50\)

\(\Rightarrow x=10\)

 

Answer 2

\(\frac{12+x}{43-x}=\frac{2}{3}\)

\(\frac{\left(12+x\right)\times3}{\left(43-x\right)\times3}=\frac{2\times\left(43-x\right)}{3\times\left(43-x\right)}\)

\(\left(12+x\right)\times3=2\times\left(43-x\right)\)

\(36+x\times3=86-2\times x\)

\(x\times3+2\times x=86-36\)

\(x\times5=50\)

      \(x=50\div5\)

      \(x=10\)