which property of algebra should first be applied to 6a-14b+3a-6+21b-18a in order determine wether its equivalent to -9a+7b-6?

The commutative property of addition should first be applied to rearrange the terms of the expression.

By applying the commutative property, the expression 6a-14b+3a-6+21b-18a can be rewritten as:

(6a + 3a - 18a) + (-14b + 21b) + (-6)

Simplifying the expression further:

-9a + 7b - 6

Therefore, the expression 6a-14b+3a-6+21b-18a is equivalent to -9a+7b-6.