Question

medal
Find the sum of the summation of 2 i minus 9, from i equals 3 to 10

Answer 1

answer choices
52
26
13
32

Answer 2

so u need help?

Answer 3

there

Answer 4

what

Answer 5

Is this the problem?
$$
\Large{
\sum_{i=3}^{10}\left ( 2i-9\right )
}
$$
If so, let's rearrange indices so that i starts at zero and simplify:
$$
\Large{
\sum_{i=0}^{7}\left ( 2(i+3)-9\right )=\sum_{i=0}^{7}\left ( 2i+6-9\right )\\
=\sum_{i=0}^{7}\left ( 2i-3\right )=\left (2\sum_{i=0}^{7}i\right )-3\times 8
}
$$
Does this make sense?

Can you finish?

Answer 6

32