1)(28+7y+4-2y-14y+2y²-42+6y)/7(2-y)<0<br>(2y²-3y-14)/7(2-y)<0<br>2y²-3y-14=0
D=9+112=121
y1=(3-11)/4=-2
y2=(3+11)/4=3,5
2-y=0
y=2
+ _ + _
-------------------------------------------------------------------
-2 2 3,5
y∈(-2;2) U (3,5;∞)
2)O3=20
80+28y-12>15y+25-30y
28y+15y>25-68
43y>-43
y>-1
y∈(-1;∞)