Question 316860
Convert to vertex form by completing the square,
{{{f(x) = x^2 + 8x + 13}}}
{{{f(x) = (x^2 + 8x+16) -3}}}
{{{f(x)=(x+4)^2-3}}}
The minimum value occurs at the vertex.
{{{fmin=f(-4)=-3}}}
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{{{ drawing( 300, 300, -8, 2, -5, 10, grid(1),circle(-4,-3,.2),graph( 300, 300, -8, 2, -5, 10, x^2 + 8x + 13)) }}}