Răspuns:
Explicație pas cu pas:
Aflați valorile rapoartelor:
a) 7x+2y/2x+3y unde x/y=0,2
x/y=0,2 ⇔ x=0,2y
(7x+2y)/(2x+3y)=(7·0,2y+2y)/(2·0,2y+3y)=(1,4y+2y)/(0,4y+3y)=3,4y/3,4y=1
b) 14x-5y/8x+3y unde y=x/0,(6)
y=x/0,(6) ⇔ y=x/(6/9) ⇔ y=x/(2/3) ⇔ y=3x/2
(14x-5y)/(8x+3y)=(14x-5·3x/2)/(8x+3·3x/2)=(2·14x-15x)/2/(2·8x+9x)/2=
(13x/2)/(25x/2)=13x/25x=13/25
c) 5x-2+15y/3x+4+9y unde 3y= 1-x
(5x-2+15y)/(3x+4+9y)=(5x-2+5·3y)/(3x+4+3·3y)=[5x-2+5·(1-x)]/[3x+4+3(1-x)]=
(5x-2+5-5x)/(3x+4+3-3x)=3/7