Answer:
[tex]a^{2}(24a^{2}+36a+12)[/tex]
Step-by-step explanation:
Area of rectangle= Length*Width
so [tex](6a^{2}+9a+3)*4a^{2}[/tex] multiply each coefficient of a times 4a^2
[tex]24a^{4}+36a^{3}+12a^{2}[/tex] then take a^2 common factor so it will be
[tex]a^{2}(24a^{2}+36a+12)[/tex]=area
