Question

Va rooog cine știeeee!!!!
​

Answer 1

Răspuns:

Explicație pas cu pas:

13.

x/y = 5/7

x = 5y/7

a)

y - x = y - 5y/7 = 7y/7 - 5y/7 = 2y/7

(y - x)/2x = (2y/7)/(10y/7) = 1/5

b)

x/(y - x) = (5y/7)/(2y/7) = 5/2

c)

x + y = 5y/7 + y = 5y/7 + 7y/7 = 12y/7

2x/(x + y) = (10y/7)/(12y/7) = 10/12 = 5/6

d)

2y/(x + y) = 2y/(12y/7) = 14y/12y = 7/6

__________________________

14.

3x/2y = 1,25

3x = 1,25*2y = 2,5y = 25y10 = 5y/2

x = 5y/6

a)

2x + y = 10y/6 + y = 10y/6 + 6y/6 = 16y/6

(2x + y)/y = (16y/6) / y = 16/6 = 8/3

b)

2x - y = 10y/6 - y = 10y/6 - 6y/6 = 4y/6

(2x - y)/x = (4y/6)/(5y/6) = 4/5

c)

4x - 3y = 20y/6 - 18y/6 = 2y/6 = y/3

(4x - 3y)/5y = (y/3)/5y = 1/15