Question 587369
{{{ ( a + b )*( a - b ) = a^2 + ab - ab - b^2 }}}
{{{ ( a + b )*( a - b ) = a^2 - b^2 }}}
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I like to do it with real numbers:
{{{ ( 7 + 5 )*( 7 - 5 ) = 49 + 35 - 35 - 25 }}}
{{{ ( 7 + 5 )*( 7 - 5 ) = 49 - 25 }}}
{{{ ( 7 + 5 )*( 7 - 5 ) = 24 }}}
{{{ 12*2 = 24 }}}
OK