Question

Va rog frumos sa ma ajutați! Repede!

Answer 1

Răspuns:

Ne folosim de proportii derivate :ai formula in poza

x/y=5/13=>x+y/y=5+13/13 => x+y/y=18/13

x/y+x=5/13+5 => x/y+x=5/18

Answer 2

Răspuns:

Explicație pas cu pas:

X/Y = 5/13

a) (x+y) / y = ?    b) x / (y+x) = ?    c) (y-x) / x = ?

____________________

x/y = 5/13  <=>  13x = 5y  => x = 5y/13

Inlocuim pe x cu 5y/13  in fiecare din cele 3 rapoarte =>

a) (x+y) / y = (5y/13 + ¹³⁾y) / y = [(5y+13y)/13] / y = (18y/13) / y =

18y/13  · 1/y = 18/13

(x+y) / y = 18/13

b) x / (y+x) = (5y/13) / (¹³⁾y  +5y/13) = (5y/13) / [(13y+5y)/13]=

= (5y/13) · (13/18y) = 5/18

x / (y+x) = 5/18

c) (y-x) / x = (¹³⁾y - 5y/13) / (5y/13) = [(13y-5y)/13] / (5y/13) =

= (8y/13) · (13/5y) = 8/5

(y-x) / x = 8/5