What is 3a^2 + a^2 added to a + 6?

To solve the expression (3a^2 + a^2 + a + 6), start by combining the like terms. The terms (3a^2) and (a^2) can be added together because they are both terms containing (a^2).

When you combine (3a^2) and (a^2), you get:

[

3a^2 + a^2 = 4a^2

]

Now, retain the remaining terms, (a) and (6), which do not have like counterparts to combine with. As a result, you now have:

[

4a^2 + a + 6

]

Thus, the final expression after simplification is (4a^2 + a + 6). This directly corresponds to the choice that presents the expression in its correct and simplified form.