4/x+2= 5/7
=>5(x+2)=4.7
5(x+2)=28
x+2=28:5
x+2=28/5
x=28/5-2
x=28/5-10/5
x=18/5
Vậy x=18/5
Nhớ k cho mk nha!
\(\frac{4}{X+2}=\frac{5}{7}\Leftrightarrow5.\left(X+2\right)=4.7\Leftrightarrow5X+10=28\Leftrightarrow5X=18\Leftrightarrow X=\frac{18}{5}\)
\(\frac{4}{x+2}=\frac{5}{7}\)=>(x+2).5=4.7
=>5x+10=28
=>5x=28-10
=>5x=18
=>x=18/5
\(\frac{4}{x+2}=\frac{5}{7}\Rightarrow4\cdot7=\left(x+2\right)\cdot5\Rightarrow28=\left(x+2\right)\cdot5\Rightarrow x+2=\frac{28}{5}\Rightarrow x=\frac{28}{5}-2=\frac{18}{5}\)
