Question 420105
{{{ 125x^3-27 = (5x - 3)(25x^2 + 15x + 9)=0}}}
{{{25x^2 + 15x + 9=0}}} gives 

{{{x = (-15 +- sqrt( 15^2-4*25*9))/50 = (-15 +- sqrt(-675))/50 = (-15 +- 15sqrt(-3))/50 = (-3 +- i*3sqrt(3))/10  }}} 

5x - 3 = 0 ==> x = 3/5.