Question 19450
 Solve {{{ 2x^3+7x^2-12x-45=0}}}

 Factor 2x^3+7x^2-12x-45
  ={{{ 2x^2(x + 3) + x^2 - 12 x -45}}}
 = {{{ 2x^2(x + 3) + (x +3)(x-15)}}}
 = {{{ (x+3)(2x^2 + x -15) }}}
 = {{{(x+3)(x+3) (2x -5) }}}
 = {{{(x+3)^2 (2x -5) }}}


 So, the roots are ...

 (or use synthetic division)


 Kenny