Ta có
\(\frac{x}{\left(-15\right)}=\frac{\left(-60\right)}{x}\)
\(\Rightarrow x\cdot x=\left(-15\right)\cdot\left(-60\right)\)
\(\Leftrightarrow x^2=900\)
\(\Rightarrow x^2=\sqrt{900}\)
\(\Rightarrow x=30\)hay \(x=\left(-30\right)\)
Vậy x=30 hoặc x=(-30)