Question

Tìm x

( x+ 4) : 20 = 5 : ( x + 4)

Answer 1

\(\left(x+4\right):20=5:\left(x+4\right)\)

\(\Leftrightarrow\left(x+4\right).\left(x+4\right)=5.20\)

\(\Leftrightarrow\left(x+4\right)^2=100\)

\(\Leftrightarrow\left(x+4\right)^2=\pm\sqrt{100}\)

\(\Leftrightarrow\left(x+4\right)=\pm10\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x+4=10\\x+4=-10\end{array}\right.\Leftrightarrow\left[\begin{array}{nghiempt}x=6\\x=-14\end{array}\right.\)

Vậy\(x\in\left\{6;-14\right\}\)

Chúc bạn học tốt !!!!!