Answer:
[tex]\large\boxed{3x^3+23x^2+63x+55}[/tex]
Step-by-step explanation:
[tex]\text{Use FOIL:}\\\\(a+b)(c+d)=ac+ad+bc+bd[/tex]
[tex](3x+5)(x^2+6x+11)\\\\=(3x)(x^2)+(3x)(6x)+(3x)(11)+(5)(x^2)+(5)(6x)+(5)(11)\\\\=3x^3+18x^2+33x+5x^2+30x+55\qquad\text{combine like terms}\\\\=3x^3+(18x^2+5x^3)+(33x+30x)+55\\\\=3x^3+23x^2+63x+55[/tex]