Question 659057
 interest= principal x rate x time
Let {{{ x }}} = amount invested at 5%
{{{ 12000 - x }}} = amount invested at 7%
{{{ I[1] = x*.05*1 }}}
{{{ I[1] = .05x }}}
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{{{ I[2] = ( 12000 - x )*.07*1 }}}
{{{ I[2] = 840 - .07x }}}
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{{{ I[1] + I[2] = 800 }}}
{{{ .05x + 840 - .07x = 800 }}}
{{{ -.02x = -40 }}}
{{{ x = 2000 }}}
{{{ 12000 - x = 12000 - 2000 }}}
{{{ 12000 - x = 10000 }}}
$2,000 = amount invested at 5%
$10,000 = amount invested at 7%