Question 36335
Solve {{{f(x) = x^2+4}}} by the quadratic formula:{{{x = (-b+-sqrt(b^2-4ac))/2a}}}

If you write your equation in the standard form:{{{ax^2+bx+c=0}}} you will see that a = 1, b = 0, and c = 4, so applying the quadratic formula:
{{{x = (-0+-sqrt(0^2-4(1)(4)))/2(1)}}}
{{{x = (-0+-sqrt(-16))/2}}}
{{{x = 4sqrt(-1)/2}}} and {{{x = -4sqrt(-1)/2}}}
{{{x = 2sqrt(-1)}}} and {{{x = -2sqrt(-1)}}} Simplify. {{{sqrt(-1) = i}}}
{{{x = 2i}}} and {{{x = -2i}}} These are the roots.

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