<span>y(x-y)
: (x-y)(х+y) = y : x+y</span>
<span>-0,5 : (1,1 -0,5) = -0.5 :
0.6</span>
(х2-2х+11х-22)-(х2+4х+5х+20)=-2
х2-2х+11х-22-х2-4х-5х-20+2=0
40
3х-15,6=0
3х=15,6
х=15,6:3
х=5,2
проверка
3*5,2-15,6=0
15,6-15,6=0
0=0
2с-4/сd-2d=2(c-2)/d(c-2)=2/d=2/5=0.4