Question 440606
the sure-fire way is to use the quadratic formula
 {{{m = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
when equation is in the form
{{{ ax^2 + b*x + c = 0 }}}
{{{2m^2 - 5m - 12 = 0 }}}
{{{ a = 2 }}}
{{{ b = -5 }}}
{{{ c = -12 }}} 
{{{m = (-(-5) +- sqrt( (-5)^2-4*2*(-12) ))/(2*2) }}}
{{{m = ( 5 +- sqrt( 25 + 96 )) / 4 }}}
{{{m = ( 5 +- sqrt( 121 )) / 4 }}}
{{{ m = ( 5 + 11)/4 }}}
(1) {{{ m = 4 }}}
and the (-) square root,
{{{ m = (5 - 11)/4 }}}
(2) {{{ m = -3/2 }}}
Now just rewrite (1) and (2) to get factors
{{{ m - 4 = 0 }}}
{{{ m + 3/2 = 0 }}}
Multiply both sides by {{{2}}}
{{{ 2m + 3 = 0 }}}
{{{ (m - 4)*(2m + 3) = 0 }}}
This works no matter how strange the coefficients are