Question 1128859
{{{ (-x )^2 = 3*( -x ) + 54 }}}
{{{ x^2 + 3x - 54 = 0 }}}
{{{ ( x + 9 )*( x - 6 ) = 0 }}}
{{{ x = 6 }}} and
{{{ -x = -6 }}}
The negative number is -6
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check answer:
{{{ (-6 )^2 = 3*(-6) + 54 }}}
{{{ 36 = -18 + 54 }}}
{{{ 54 = 54 }}}