Question

d) va roooog, chiar am nevoie urgenta

Answer 1

Răspuns:

Explicație pas cu pas:

 

Answer 2

Explicație pas cu pas:

$\dfrac{x}{y} = \dfrac{2}{7} \iff \dfrac{x}{2} = \dfrac{y}{7} = k \\ x = 2k \ ; \ y = 7k$

a)

$\dfrac{2x}{3y} = \dfrac{2}{3} \cdot \dfrac{x}{y} = \dfrac{2}{3} \cdot \dfrac{2}{7} = \bf \dfrac{4}{21}$

b)

$\dfrac{x + y}{y} = \dfrac{x}{y} + \dfrac{y}{y} = \dfrac{2}{7} + 1 = \bf \dfrac{9}{7}$

c)

$\dfrac{y - x}{x} = \dfrac{7k - 2k}{2k} = \dfrac{5k}{2k} = \bf \dfrac{5}{2}$

d)

$\dfrac{2x + 3y}{5y} = \dfrac{2 \cdot 2k + 3 \cdot 7k}{5 \cdot 7k} = \\ = \dfrac{4k + 21k}{35k} = \dfrac{25k}{35k} = \bf \dfrac{5}{7}$