aduci laacelasi numitor in paranteza, adica 15
(15x + 28)/15 * 3/2 = 21/4
(15*3x+28*3)/15*2=21/4
(45x +84)/30=21/4 reduci fractiile
45x*4 +84 * 4 = 21 *30
180x +336 =630
180x = 630 -336
180 x = 294
x = 294 /180
218/100 * 1/y = 100/1000 reduci 2 zerouri
218/100y =1/10
100y = 2180
y = 2180/100
y = 218/10
y = 21.8
