Răspuns:
Explicație pas cu pas:
x/y = 6/10
x/y = 3/5 => x = 3/5 * y
a) (x + y) / (3x + y) = (3/5 * y + y) / (9/5 * y + y) = (8y/5) / (14y/5) = (8y/5) * (5/14y)
= 4y/7
b) (8y/5) / (21y/5 - y) = (8y/5) / (16y/5) = (8y/5) * (5/16y) = 1/2
c) (2y/5) * (3y/5 + 7y) = (2y/5) * (5/38y) = 1/19