1) x² + 2x - 8 = (x² + 2x + 1) - 9 = (x + 1)² - 3² = (x + 1 - 3)(x + 1 + 3) =
= (x - 2)(x + 4)
2) x² - 6x + 5 = (x² - 6x + 9) - 4 = (x - 3)² - 2² = (x - 3 - 2)(x - 3 + 2) =
= (x - 5)(x - 1)
3) x² + 12x + 11 = (x² + 12x + 36) - 25 = (x + 6)² - 5² = (x + 6 - 5)(x + 6 + 5) =
= (x + 1)(x + 11)
4) x² - 4x - 5 = (x² - 4x + 4 ) - 9 =(x - 2)² - 3² = (x - 2 - 3)(x - 2 + 3) =
= (x - 5)(x + 1)
(X+10)^2=(2-X)^2
X^2+20X+100=4-4X+X^2
24X=-96
X=-96:24
X=-4
X1+x1= -b
x1*x2= c
1) x2-2x-3=0
x1 = 3
x2 = -1
2) x2+12x+27=0
x1 = 3
x2 = 9
2x+1/5=1
2x+0,2=1
2x=0,8
X=0,4
У наименьшее равно -1
у наибольшее равно 1