Answer:
20 terms
Step-by-step explanation:
<u>Given AP with the first two terms:</u>
<u>Common difference: </u>
<u>To find </u>
<u>Since Sₙ = -30</u>
<u>Solving the quadratic equation we get:</u>
So the sum of 20 terms will add up - 30
3.303e+13 that is approximately
10 degrees
7 - (-3) = 7+3 = 10 degrees