(2/3)/(4/9 х - 4/9) +1/20=4/5
(2/3)/(4/9 х - 4/9)=16/20 - 1/20
2/(3(4/9 х-4/9)=15/20=3/4
2 * 3/4=3*3(4/9 х - 4/9)
3/2=9 * 4/9*(х-1)
3/2=4(х-1)
3=4*2(х-1)
х-1=3/8
х=3/8+1
х=1 3/8
(5/7)/(6/7 х+3/7) -1/2=1/6
5/(7*3/7(2х+1)) =1/6+3/6
5/(3(2х+1))=4/6=2/3
5=2(2х+1)
2х+1=5/2
2х=2 1/2 - 1
2х=1 1/2
х=1 1/2 : 2
х=3/2 * 1/2
х=3/4