1. x³- 1=(х-1)(х²+х+1)
2. 27 + a³=(3+а)(9-3а+а²)
3. 216 - y³=(6-у)(36+6у+у²)
4. 1/8a³ + b³=(1/2а+b)(1/4a²-1/2a+b²)
5. a⁶ - 8=(a²-2)(a⁴+2a²+4)
6. a³b³ - c³=(ab-c)(a²b²+abc+c²)
7. a³ - b¹⁵c¹⁸=(a-b⁵c⁶)(a²+ab⁵c⁶+b¹⁰c¹²
8. 125c³d³ +0,008b³=(5cd+0,2b)(25c²d²-bcd+0,04b²)
(х-1)(х²+6х+9)=5(х+3)
(х-1)(х+3)²=5(х+3)
(х-1)(х+3)=5
х²+3х-х-3=5
х²+2х-8=0
D=2²-(-4*8)=4+32=36
х1=(-2+6)/2=2
х2=(-2-6)/2=-4
Ответ: -4 ; 2
{2a+b=3, <=> {2b+b = 3 <=> {3b = 3, <=> {b = 1,
{a−b=0 {a = b {a=b {a = 1
An = 3n - 4
a1 = - 1
a40 = 116
S40 = ?
S40 = (a1 + a40)/2*40 = 20*( - 1 + 116) = 2300