Question 804653
{{{ 5n + 8n = 3 + 2n }}}
Add together the terms on the left side
Doing this does not change the 
left side at all
{{{ 13n = 3 + 2n }}}
Subtract {{{ 2n }}} from both sides
{{{ 13n = 3 + 2n }}}
{{{ -2n = -2n }}}
{{{ 11n = 3 }}}
Divide both sides by {{{ 11 }}}
{{{ n = 3/11 }}}
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check the answer:
{{{ 5n + 8n = 3 + 2n }}}
{{{ 5*(3/11) + 8*(3/11) = 3 + 2*(3/11) }}}
{{{ 15/11 + 24/11 = 33/11 + 6/11 }}}
{{{ 39/11 = 39/11 }}}
OK