Question

daca x si y sunt direct proporționale cu 2 si 5 => 3x+y pe 2y =

Answer 1

{ x,y } d.p { 2,5 }
----------------------------/-------
3x+y / 2y = 
----------------------------//------

x / 2 = y / 5 = K

x / 2 = K => x =  2 K
y / 5 = K  => y = 5 K

 ( 3 x 2 K + 5 K )  / 2 x 5 K = 

= ( 6 K + 5 K ) / 10 K

= 11 K / 10 K

= 11 / 10

Answer 2

x/2 = y/5 => x/y = 2/5
(3x+y)/2y = (3x/y + y/y)/(2y/y) = (3x/y + 1)/2 = (3*2/5+1)/2 = (6/5+5/5)/2 = 11/5:2 = 11/5 x 1/2 = 11/10