The solutions for [tex]f(x) = x^{2}+2\cdot x + 1 = 0[/tex] are [tex]x_{1} = x_{2} = -1[/tex].
We can estimate the roots by a numerical approach, which consists in evaluating the quadratic function ([tex]f(x) = x^{2}+2\cdot x + 1 = 0[/tex]) for a set of values of [tex]x[/tex]. We consider the set of values between [tex]-4\le x \le 4[/tex]:
[tex]\,\,\,\,\,\,x \,\,\,\,\,\,\,\,f(x)\\-4\,\,\,\,\,\,\,\,\,\,\,\,9\\-3\,\,\,\,\,\,\,\,\,\,\,\,4\\-2\,\,\,\,\,\,\,\,\,\,\,\,1\\-1\,\,\,\,\,\,\,\,\,\,\,\,0\\.\,\,\,0\,\,\,\,\,\,\,\,\,\,\,\,\,1\\.\,\,\,1\,\,\,\,\,\,\,\,\,\,\,\,\,4\\.\,\,\,2\,\,\,\,\,\,\,\,\,\,\,\,\,9\\.\,\,\,3\,\,\,\,\,\,\,\,\,\,\,\,\,16\\.\,\,\,4\,\,\,\,\,\,\,\,\,\,\,\,\,25\\[/tex]
According to the previous input, we conclude that roots of the quadratic formula are [tex]x_{1} = x_{2} = -1[/tex].
The solutions for [tex]f(x) = x^{2}+2\cdot x + 1 = 0[/tex] are [tex]x_{1} = x_{2} = -1[/tex].
