a) 11^3=(10+1)^3=10^3+3*10^2*1+3*10*1^2+1^3=1000+300+30+1=1331
b) 29^3=(30-1)^3=30^3-3*30^2*1+3*30*1^2-1^3=27000-2700+90-1=24389
5(х+1)-13>=7х+20
5х+5-13>=7х+20
5х-8>=7х+20
5х-7х>=20+8
-2x>=28
X>=-14
(-14;+бесконечность)
8= 2^3
81= 9^2
125= 5^3
64= 8^2
0,001= 0,1^3
3 3/8 = 27/8 =(3/2)^3
36/25= (6/5)^2
14b+(b+7)(b-7)+(b-7)^2=14b+b^2-49+b^2-14b+49=2b^2