Answer:
[tex]\bold\purple{Quadratic \: \: eq {}^{n} = x {}^{2} - ( \alpha + \beta )x + \alpha \beta} \\ [/tex]
Sum of roots ,
[tex]( \alpha + \beta ) = (3 + 9) = 12[/tex]
Product of roots ,
[tex]( \alpha \beta ) = (3)(9) = 27[/tex]
Substituting the values in the above equation ,
[tex]\bold{x {}^{2} - ( \alpha + \beta )x + \alpha \beta} \\\\ \bold{⇢ x {}^{2} - (12)x + 27} \\\\ \bold\blue{ ⇢x {}^{2} - 12x + 27}[/tex]
hope helpful~