Question 441527
By inspection, I see that
{{{ x^2 + 16x + 64 = ( x + 8 )^2 }}}
To find x-intercepts,
{{{ f(x) = 0 }}}
{{{ ( x + 8 )^2 = 0 }}}
Take the square root of bpth sides
{{{ x + 8 = 0 }}}
{{{ x = -8 }}}
The x-intercept is a "double root" at (-8,0)
Here's the plot:
{{{ graph( 400, 400, -16, 2, -2, 10, x^2 + 16x + 64) }}}