Question

dau coroana !!! va rog​

Answer 1

Răspuns:

Y/(x+y)=3/4 =>[ y/(x+y-y)]/[3/(4-3)] => y/x=3/1 =k => y=3k si x=k. Inlocuim (2k+9k)/(k+3k)=11k/4K =11/4=2,75

Answer 2

y/x+y = 3/4

y=3(x+y)/4

x+y=4y/3 atunci x =4y/3 -y= y/3

2x+3y=2(x+y) + y= 2* 4y/3 + 3(x+y)/4=

=8y/3 + 3x+3y/4= 8y/3 + y+3y/4=8y/3 + 4y/4=8y/3 + y= 16y/6+ 6y/6=22y/6=11y/3

2x+3y/x+y=( 11y/3)/4y/3= 11y/3 * 3/4y=11/4= 2,75

R: D.2,75