X в квадрате - 6x - 16 = 0

X^2-6x-16=0; x1*x2=-16; x1+x2=6; x1=8; x2=-2; Ответ: х1=8; х2=-2; Извините все съехало : D

X²-6x-16=0

D=b²-4ac

x1 = (-b-√D) / (2a)

x2 = (-b+√D) / (2a)

D = (-6) ²-4*1 * (-16) = 36+64=100

x1 = (- (-6) - √100) / (2*1) = (6-10) / 2=-4/2=-2

x1 = (- (-6) + √100) / (2*1) = (6+10) / 2=16/2=8

D/4 = (b/2) ²-ac

x1 = (-b/2-√ (D/4)) / a

x1 = (-b/2+√ (D/4)) / a

D/4 = (-3) ²-1 * (-16) = 9+16=25

x1 = (- (-3) - √25) / 1 = (3-5) / 1=-2

x1 = (- (-3) + √25) / 1 = (3+5) / 1=8