Question 147916
x^2 + 3x - 9 = 0 then {{{x = (-3 +- sqrt( 3^2-4*1*(-9) ))/(2*1) }}}=
{{{x = (-3 +- sqrt( 45 ))/2 }}}

(3x+5)(x-3)=3x^2+5x-9x-15 = 3x^2-4x-15
3x(2x2 + 5x - 4) = 6x^3+15x^2-12x

6x^2 - 27x - 15=0 then {{{x = (27 +- sqrt( (-27)^2-4*6*(-15) ))/(2*6) }}}=
{{{x = (27 +- sqrt( 1089 ))/12 }}}={{{x = (27 +- (33))/12 }}}
then x=5 or x=-1/2


then 6x^2 - 27x - 15= 6(x-5)(x+1/2)