I know you want it in standard quadratic form but I don't think it can be done since 4a * 6a^2 = 24a^3
Multiply 4a to 6a^2, -a and 2
so: 24a^3, -4a^2, and 8a
=24a^3-4a^2+8a
Now multiply 2 to 6a^2, -a, and 2
=12a^2-2a+4
Combine like terms of 24a^3-4a^2+8a and 12a^2-2a+4
=24a^3+8a^2-6a+4