Question

x phần -15 = - 60 phần x 

tìm x trong tỉ lệ thức sau

 

 

Answer 1

\(\dfrac{x}{-15}=\dfrac{-60}{x}=>x^2=-60.-15=900=>x=30\)

Answer 2

\(\dfrac{x}{-15}=\dfrac{-60}{x}\)

⇔\(x.x=-15.-60\)

⇔\(x^2=900\)

⇔\(\left[{}\begin{matrix}x=\sqrt{900}\\x=-\sqrt{900}\end{matrix}\right.\)

⇔\(\left[{}\begin{matrix}x=30\\x=-30\end{matrix}\right.\)

Answer 3

\(\dfrac{x}{-15}=\dfrac{-60}{x}\)

\(\Leftrightarrow x^2=900\)

hay \(x\in\left\{30;-30\right\}\)