X²+20x+100=4-4x+x²
x²+20x+4x-x²=4-100
24x=-96
x= -96÷24
x= -4
A21=30+16sqrt(3)=a1+20d
2+20d=30+16sqrt(3)
20d=28+16sqrt(3)
d=1.4+0.8sqrt(3)≈2.78
Х^3-х^2+х+2х^2-2х+2+8+4х+2х^2-4х-2х^2-х^3=х^2-х+10
B1 = - 7
b2 = 14
q = b2/b1 = - 14/7 = - 2
b3 =b1*q^2 = (-7)*(-2)^2 = - 7*4 = - 28