2х+8=3х+40
3х-2х=8-40
х=-32
A+5b+a² - 25b²=(a+5b)+(a+5b)(a-5b)=(a+5b)(1+a-5b)
a³x² - ax - 4a³ - 2a=a³(x² - 4)-a(x-2)=a³(x-2)(x+2)-a(x-2)=a(x-2)(a²(x+2) - 1)=a(x-2)(a²x+2a-1)
a³ -27+a² -3a=(a-3)(a²+3a+9) +a(a-3)=(a-3)(a²+3a+9+a)=(a-3)(a²+4a+9)
= Сos(56° - 11°)= Cos45° = √2/2
Log3-x(x^2-x-1)=1
ODS x∈(-∞, (1-√5)/2 )∪ (1+√5)/2,2)∪(2,3)
x^2-x-1=(3-x)^1
x^2-1=3
x^2=3+1
x^2=4
x=<span>±2
x</span>₁=2
x₂=-2