1) y^3+21*y^2+147*y+343-y^3-21*y^2>0
147y+343>0
147y>-343
y>-2.(3)
2)216-54y+18y^2-y^3+y^3-18y^2<0
216-54y<0
54y>216
y>4
6cd•2ac=c в квадрате •12•a•d
4m•(-5n)•(-8k)=160•n•k•m
Y+1.5y+y+4=25
3.5y=25-4
3.5y=21
y=21/3.5
y=6
3.5*6=21
21=21
1
(ab+ac)²/(ab²-ac²)=a²(b+c)/a(b²-c²)=a(b+c)/(b-c)(b+c)=a/(b-c)
2
1)1/c-1/(10-c)=(10-c-c)/c(10-c)=(10-2c)/c(10-c)=2(5-c)/c(10-c)=2(c-5)/c(c-10)
2)25/(c-5) -(c-5)=(25-c²+10c-25)/(c-5)=(10c-c²)/(c-5)=c(10-c)/(c-5)
3)2(c-5)/c(c-10) * c(10-c)/(c-5)=-2