Question

Dacă $\frac{x}{3} = \frac{5}{y}$calculează 4xy-15​

Answer 1

$\frac{x}{3} = \frac{5}{y}$

$xy = 3 \times 5 = 15$

$4xy - 15 = 4 \times 15 - 15 = 60 - 15 = 45$

Answer 2

$\it \dfrac{x}{3}=\dfrac{5}{y} \Rightarrow xy=15|_{\cdot4} \Rightarrow 4xy=60|_{-15} \Rightarrow4xy-15=45$