Identify the common difference
-21,-18,-15,-12

d = 3

Step-by-step explanation:

The common difference d between consecutive terms is

d = - 18 - (- 21) = - 18 + 21 = 3

d = - 15 - (- 18) = - 15 + 18 = 3

d = - 12 - (- 15) = - 12 + 15 = 3

3. (5x + 1) - (-10x + 6)

simplify the answer choice. combine like terms. remember to distribute the negative to the terms inside the second parenthesis. also remember that two negatives = one positive, and one of each sign = negative.

- (-10x + 6) = + 10x - 6

simplify. combine like terms:

5x + 1 + 10x - 6

5x + 10x + 1 - 6

15x - 5

∴ it is your answer

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