Question

x : 2 = y : 3 và x ² + y ² = 325

Answer 1

\(\dfrac{x}{2}=\dfrac{y}{3}\Rightarrow x=\dfrac{2}{3}y\)

Thay vào \(x^2+y^2=325\), ta có: 

\(\dfrac{4}{9}y^2+y^2=325\\ \Leftrightarrow\dfrac{13}{9}y^2=325\\ \Leftrightarrow y^2225\\ \Leftrightarrow\left[{}\begin{matrix}y=15\Rightarrow x=10\\y=-15\Rightarrow x=-10\end{matrix}\right.\)

 

Answer 2

Đặt x/2=y/3=k

=>x=2k; y=3k

x^2+y^2=325

=>13k^2=325

=>k^2=25

TH1: k=5

=>x=10; y=15

TH2: k=-5

=>x=-10; y=-15

Answer 3