Question 941011
Let the integer = {{{ k }}}
{{{ 5k*( k + 6 ) = 35 }}}
{{{ 5k^2 + 30k = 35 }}}
Divide both sides by {{{ 5 }}}
{{{ k^2 + 6k - 7 = 0 }}}
{{{ ( k + 7 )*( k - 1 ) = 0 }}}
{{{ k = 1 }}}
{{{ k = -7 }}}
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Check for {{{ k = 1 }}}
{{{ 5k*( k + 6 ) = 35 }}}
{{{ 5*1*( 1 + 6 ) = 35 }}}
{{{ 5*7 = 35 }}}
{{{ 35 = 35 }}}
OK