Step: 1
(a + 3 - 3a - 3 + 2a - 3 + 7a)
[Original expression.]
Step: 2
= (a - 3a + 2a + 7a) + (3 - 3 - 3)
[Use the commutative property of addition to reorder the terms.]
Step: 3
= 7a - 3
[Combine like terms.]
Step: 4
Among the choices, the expression 7a - 3 is the simplified form of the expression.
Correct Answer is : 7a - 3