Question

Tìm x trong các tỉ lệ thức:

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

Answer 1

\(\dfrac{x}{-15}=\dfrac{-60}{x}\Rightarrow x^2=\left(-60\right)\times\left(-15\right)=900\)

Vậy x²=900=>x=30

Answer 2

\(\dfrac{x}{-15}=\dfrac{-60}{x}\\ x.x=-60.\left(-15\right)\\ x^2=900\\ x^2=30^2=\left(-30\right)^2\\ \Rightarrow x=\pm30\)

Answer 3

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

\(\Leftrightarrow x.x=-15.\left(-60\right)\)

\(\Leftrightarrow x^2=900\)

\(\Rightarrow x^2=\left(\pm30\right)^2\)

\(\Rightarrow x=30\) hoặc \(x=-30\)