Question 731262
{{{ n^2 + n - 56 }}}
You can try to complete the square
first set the equation equal to zero
{{{ n^2 + n - 56 = 0 }}}
Subtract {{{ 56 }}} from both sides
{{{ n^2 + n  = 56 }}}
Take 1/2 of the co-efficient of {{{ x }}}
square it and add it to both sides
{{{ n^2 + n  + (1/2)^2 = (1/2)^2 + 56 }}}
{{{ n^2 + n  + 1/4 = 1/4 + 224/4 }}}
{{{ n^2 + n  + 1/4 = 225/4 }}}
{{{ ( n + 1/2 )^2 = (15/2)^2 }}}
Take the square root of both sides
{{{ n + 1/2 = 15/2 }}}
{{{ n - 14/2  = 0 }}}
{{{ n - 7 = 0 }}}
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also,
{{{ n + 1/2 = -15/2 }}}
{{{ n + 16/2  = 0 }}}
{{{ n + 8 = 0 }}}
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{{{ ( n-7 )*( n+8 ) = 0 }}}
{{{ n^2 + n - 56  = ( n-7 )*( n+8 ) }}}