Question

Tìm x và y biết \(\frac{x}{3}\)=\(\frac{y}{5}\) và \(x.y=60\)\(\)

Answer 1

Đặt \(\frac{x}{3}=\frac{y}{5}=k\)

Ta có: \(x=3k;y=5k\)

\(\Rightarrow xy=15k^2\)

\(\Rightarrow60=15k^2\)

\(\Rightarrow k^2=60:15=4\)

\(\Rightarrow k=2\)

\(\Rightarrow x=2.3=6\)

     \(y=2.5=10\)

Vậy x = 6 và y = 10

Answer 2

x=6.

y=10.

Answer 3

x=6;y=10.

Answer 4

Dat : \(\frac{x}{3}=\frac{y}{5}=k\)

\(\Rightarrow x=3k,y=5k\)

Do \(x\times y=60\)

nen \(3k.5k=60\Leftrightarrow15k^2=60\)

\(\Leftrightarrow k^2=4\Rightarrow\orbr{\begin{cases}k=2\\k=-2\end{cases}}\)

+) \(k=2\Rightarrow\hept{\begin{cases}x=6\\y=10\end{cases}}\)

+) \(k=-2\Rightarrow\hept{\begin{cases}x=-6\\y=-10\end{cases}}\)