Question

Qual sao as raízes da equação x2-2x-3=0?

Answer 1

x²-2x-3=0
a= 1 b=-2 c= -3
Δ= b²-4ac
Δ= (-2)² -4·1·(-3)
Δ= 4+12
Δ= 16

x= -b +/- √Δ 
            2a

x= - (-2) +/- √16
           2·1

x= 2 +/- 4
        2
x'= 3
x''= -1

S:[-1,3]

Answer 2

$x^{2} -2x-3=0 \\ \\ \Delta=(-2)^2-4.1.(-3) = 4+12=16 \\ \\ x=\frac{2 \pm \sqrt{16}}{2} =\frac{2 \pm 4}{2} \\ \\ x_1=\frac{2-4}{2}=-1 \\ \\ x_2=\frac{2+4}{2}=3$