ax^2+bx+c=0
x_"1,2"=(-b±sqrt(b^2-4*a*c))/(2*a)" the quadratic formula"
x^2-5x-1=0
a=1" "b=-5" "c=-1
Delta=sqrt(b^2-4*a*c)
Delta=sqrt(25+4*1*1)
Delta=±5,39
x_1=(-b-Delta)/(2*a)
x_1=(5-5,39)/(2*1)
x_1=(0,39)/2
x_1=0,195
x_2=(-b+Delta)/(2*a)
x_2=(5+5,39)/2
x_2=(10,39)/2
x_2=5,195