Question

What is the sum of the series?

Answer 1

the answer choices are −220
−110
−95
110

Answer 2

This is an arithmetic series. Its sum can be found with this formula:
\(\frac{1}{2}\cdot NoOfTerms \cdot (First~term+Last~term)\)

Answer 3

still confused on what to do

Answer 4

No of terms: 20
First Term: 4 (set n=1)
Last term: -15 (set n=20)

Put these numbers in the formula...

Answer 5

im stil not getting it I keep coming up with a two digit answer @ZeHanz

Answer 6

\(\frac{1}{2}\cdot 20 \cdot(4+-15)=10\cdot -11=-110\)

Answer 7

wow , thanks

Answer 8

yw!