Question 273231
p^2 + 8p + 16 = 0 using quadratic formula

ap^2 + bp + c^2 = 0
{{{p = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
where a=1, b=8, c=16
{{{p = (-8 +- sqrt( 8^2-4*1*16 ))/(2*1) }}}
{{{p = (-8 +- sqrt( 64-64))/2 }}}
{{{p = (-8 +- sqrt(0))/2 }}}
{{{p = -8/2 }}}
{{{p = -4 }}}
(p+4)(p+4) = p^2 + 4p + 4p + 16 = p^2 + 8p + 16 (used foil)
The answers are -4 and -4 or just -4.