Answer:
S
ThenSn=n(a1+an)2Sn=n(a1 + an)2 , where nn is the number of terms, a1a1 is the first term and anan is the last term. The sum of the first nn terms of an arithmetic sequence is called an arithmetic series .
Step-by-step explanation:
I think the answer is x=30
Answer:
E. Step 3
Step-by-step explanation:
Step 2:
2x + 18 = 4x + <u>28 + 2</u>
Step 3:
2x + 18 = 4x + <u>26</u>
She subtracted instead of adding (see bold and underline)
