Question

Stiind ca x supra y este 0,7 aflati valoarea raportului :3 ori x plus 4 ori y supra 5x plus 2 y. URGENT!

Answer 1

Salut! :)

Răspuns:

$\dfrac{61}{55}$

Explicație pas cu pas:

$0,7 = \frac{7}{10}$

$\dfrac{x}{y} = \dfrac{7}{10} \Longrightarrow y = \dfrac{10x}{7}$

$\dfrac{3x + 4y}{5x + 2y} = \dfrac{3x + 4 \cdot \frac{10x}{7} }{5x + 2\cdot\frac{10x}{7} } =$

$= \dfrac{3x +\frac{40x}{7} }{5x + \frac{20x}{7} } =$

$= \dfrac{\dfrac{61}{7} x}{\dfrac{55}{7} x} =$

$= \dfrac{61}{55}$

Answer 2

Răspuns:

x/y=0,7=>x/y=7/10

10x=7y=>x=7y/10

(3x+4y)/(5x+2y)=(3·7y/10+4y)/(5·7y/10+2y)=(21y/10+¹⁰⁾4y)/(35y/10+¹⁰⁾2y)=(21y+40y)/35y+20y)=61y/55y=61/55