Question 581741
{{{ 3a + 7 = a + 9 }}}
As long as you do the same thing to both sides,
the equation is still true
Subtract {{{a}}} from both sides
{{{ 3a - a + 7 = a - a + 9 }}}
{{{ 2a + 7 = 9 }}}
Now subtract {{{7}}} from both sides
{{{ 2a + 7 - 7 = 9 - 7 }}}
{{{ 2a = 2 }}}
Now divide both sides by {{{2}}}
{{{ (2/2)*a = (2/2) }}}
{{{ a = 1 }}} answer
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check:
{{{ 3a + 7 = a + 9 }}}
{{{ 3*1 + 7 = 1 + 9 }}}
{{{ 3 + 7 = 10 }}}
{{{ 10 = 10 }}}
OK