(a + b)2 = a2 + 2ab + b2<span> (a – b)2 = a2 – 2ab + b2</span><span>a2 – b2 = (a – b)(a + b)</span><span>(a + b – c)2 = a2 + b2 + c2 + 2ab – 2ac – 2bc</span><span>(a + b + c)2 = a2 + b2 + c2 + 2ab + 2ac + 2bc</span>
Х³ - 2х² - 9х + 18 = 0
х²(х - 2) - 9(х - 2) = 0
(х - 2)(х² - 9) = 0
(х - 2)(х - 3)(х + 3) = 0
х1 = 2 х2 = 3 х3 = -3
1. 6x+10 =<3
6x=<-7
x=< - 7/6
(-бесконечность; -7/6]
2.-4x+3>=5
-4x>=2
x>=-1/2
(-бесконечность;-1/2]
3. 2x-3>5x
2x-5x>3
-3x>3
x>-1
(-бесконечность; -1)
да, я не умею писать "бесконечность" значком)