Question 828420
{{{ x*y = -3136 }}}
{{{ x + y = 15 }}}
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{{{ y = 15 - x }}}
By substitution:
{{{ x*( 15-x ) = -3136 }}}
{{{ -x^2 + 15x + 3136 = 0 }}}
Use the quadratic formula
{{{ x = ( -b +- sqrt( b^2 - 4*a*c )) / (2*a) }}}
{{{ a = -1 }}}
{{{ b = 15 }}}
{{{ c = 3136 }}}
{{{ x = ( -15 +- sqrt( 15^2 - 4*(-1)*3136 )) / (2*(-1)) }}}
{{{ x = ( -15 +- sqrt( 225 + 12544)) / (-2) }}}
{{{ x = ( -15 +- sqrt( 12769)) / (-2) }}}
{{{ x = ( -15 + 113 )/(-2) }}}
{{{ x = 98/(-2) }}}
{{{ x = -49 }}}
and, also
{{{ x = ( -15 - 113 )/(-2) }}}
{{{ x = -128/(-2) }}}
{{{ x = 64 }}}
The numbers are 64 and -49 
check:
{{{ x*y = -3136 }}}
{{{ 64*(-49) = -3136 }}}
{{{ -3136 = -3136 }}}
and
{{{ x + y = 15 }}}
{{{ 64 +(-49) = 15 }}}
{{{ 15 = 15 }}}
OK