Question 48578
f(x) = x^2 + 4 
Let:
a=1
b=0
c=4
.
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} [Plug-in the values]
.
{{{x = (-0 +- sqrt( 0^2-4(1)(4) ))/(2(1)) }}} 
{{{x = (-0 +- sqrt( -16) ))/(2)) }}} [Simplify]
{{{x = (-0 +- 4i)/2 ))) }}}[Cancel out]
x = +-2i [x = -2i or x = +2i] [Final answers]
.


{{{ graph( 300, 200, -5, 6, -5, 10, x^2 + 4) }}} 

.
.



g(x) = x^2 + x + 12 
Let:
a = 1
b = 1
c = 12
.
.
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
.
{{{x = (-1 +- sqrt( 1^2-4(1)(12) ))/(2(1)) }}} 
.
{{{x = (-1 +- sqrt( -47) ))/(2) }}}
.
{{{x = (-1/2 +- ( -47/2) )) }}}
.
{{{x = ((-1/2) +- (47i/2))}}}
.
.
{{{ graph( 400, 400, -13, 13, -2, 25, x^2 + x + 12 ) }}}