Question

(3a^2–7a^2-3a^4)+(4a^2-a^4-4a)

Answer 1

Rearrange the equation

(3a^2–7a^2-3a^4)+(4a^2-a^4-4a)

(-3a^4 +3a^2 - 7a^2) + (-a^4 + 4a^2 - 4a)

-4a^4 - 4a

-4a ( a^3 + 1)

Answer 2

There is no need for parenthesis, so you can just combine like terms.
$3 a^{2} -7 a^{2} - 3a^{4} + 4 a^{2} - a^{4} -4a \\ \\ = -4 a^{4} - 4a \\ \\ = -4a( a^{3} + 1)$