x²-x-12
a) a=1
b= -1
c= -12
b) ∆=b²-4ac
∆= (-1)²-4.1.(-12)
∆= 1+ 48
∆= 49
c) x1=
[tex] \frac{ - b + \sqrt{delta} }{2a} = \frac{ - ( - 1) + \sqrt{49} }{2.1} = \frac{1 + 7}{2} = \frac{8}{2} = 4[/tex]
x2=
[tex] \frac{ - b - \sqrt{delta} }{2a} = \frac{ - ( - 1) - \sqrt{49} }{2.1} = \frac{1 - 7}{2} = \frac{ - 6}{2} = - 3[/tex]
