To get your quadratic equation, you're going to want to use the FOIL method.
3x(5x) + 3x(- 2) + 3(5x) + 3(- 2)
Simplify to get [tex]15 x^{2} -6x+15x-6[/tex]
Combine like terms:
[tex]15 x^{2} +9x-6[/tex]
Your quadratic term is [tex]15x^{2} [/tex]
Your linear term is [tex]9x[/tex]
Your constant is [tex]-6[/tex]
