Question 1067399
Her age now is {{{ x }}} 
6 yrs ago her age was {{{ x - 6 }}}
In 12 yrs her age will be {{{ x + 12 }}}
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{{{ x + 12 = 3*( x - 6 ) }}}
{{{ x + 12  = 3x - 18 }}}
{{{ 12 = 2x - 18 }}}
{{{ 2x = 12 + 18 }}}
{{{ 2x = 30 }}}
{{{ x = 15 }}}
She is 15 now
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check:
{{{ x + 12 = 3*( x - 6 ) }}}
{{{ 15 + 12 = 3*( 15 - 6 ) }}}
{{{ 27 = 3*9 }}}
{{{ 27 = 27 }}}
OK