Question 750568
{{{ x^2 - 4x = 5 }}}
{{{ x^2 - 4x + (-4/2)^2 = 5 + (-4/2)^2 }}}
{{{ x^2 - 4x + 4 = 5 + 4 }}}
{{{ x^2 - 4x + 4 = 9 }}}
{{{ ( x - 2 )^2 = 3^2 }}}
{{{ x - 2 = 3 }}}
{{{ x = 5 }}}
and, also,
{{{ x - 2 = -3 }}}
{{{ x = -1 }}}
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check:
{{{ ( x - 5 )*( x + 1 ) = x^2 - 4x - 5 }}}
{{{ x^2 - 4x = 5 }}}
OK