Question 120077
{{{ x^2 + 4x + 4  =0}}}
The quadratic formula is:
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
The discriminant is {{{ b^2-4*a*c }}}
The equation given is of the form  {{{ax^2 + bx + c = 0}}}
{{{ b^2-4*a*c = 4^2 - 4*1*4}}}
{{{4^2 - 4*1*4 = 0}}}
The discriminant is 0, so the quadratic equation says there is 1 root
{{{(-b +- sqrt( b^2-4*a*c ))/(2*a) = -b/(2a)}}}
{{{-b/(2a) = -4/(2*1)}}}
The curve touches the x-axis at 1 point (-2,0)
{{{ graph( 600, 600, -10, 10, -10, 10, x^2 + 4x + 4) }}}