The right chose is -9x+3= the others are not hope this helped
Answer: The correct answer is D.
Step-by-step explanation:
I just did it, and it was correct.
14 + 28 + 42 + 56 + … 280
= 14 (1 + 2 + 3 + 4 + … + 20)
= 14 × 20 × 21 / 2
= 2940
where we use the well-known identity,
