Question 962829
{{{ x^2 + 9x + 8 }}}
{{{ x^2 + 9x + ( 9/2 )^2 = -8 + ( 9/2 )^2 }}}
{{{ x^2 + 9x + 81/4 = -32/4 + 81/4 }}}
{{{ x^2 + 9x + 81/4 = 49/4 }}}
{{{ ( x + 9/2 )^2 = ( 7/2 )^2 }}}
Take the square root of both sides
{{{ x + 9/2 = 7/2 }}}
{{{ x = -1 }}}
and, taking the negative square root of {{{ 7/2 }}},
{{{ x + 9/2 = -7/2 }}}
{{{ x = -8 }}}
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check:
{{{ x + 1 = 0 }}}
{{{ x + 8 = 0 }}}
{{{ ( x + 1 )*( x + 8 ) = 0 }}}
{{{ x^2 + 9x + 8 = 0 }}}
OK