Gray Hodgson
10/20/2023 · High School
4. \( \left[\sum_{m=2}^{7}(4 m-13)\right]\left[\sum_{m=1}^{9}(2 m-2)\right] \) 5. \( \sum_{s=5}^{11}(7 s-4)-6 \sum_{s=6}^{13}(-3 s-2) \)
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Tutor-Verified Answer
Step-by-step Solution
Let's solve each expression step by step.
### Problem 4:
\[
\left[\sum_{m=2}^{7}(4 m-13)\right]\left[\sum_{m=1}^{9}(2 m-2)\right]
\]
**Step 1: Calculate the first sum \(\sum_{m=2}^{7}(4m-13)\)**
We can evaluate this sum by substituting the values of \(m\) from 2 to 7:
\[
\begin{align*}
m = 2: & \quad 4(2) - 13 = 8 - 13 = -5 \\
m = 3: & \quad 4(3) - 13 = 12 - 13 = -1 \\
m = 4: & \quad 4(4) - 13 = 16 - 13 = 3 \\
m = 5: & \quad 4(5) - 13 = 20 - 13 = 7 \\
m = 6: & \quad 4(6) - 13 = 24 - 13 = 11 \\
m = 7: & \quad 4(7) - 13 = 28 - 13 = 15 \\
\end{align*}
\]
Now, summing these results:
\[
-5 + (-1) + 3 + 7 + 11 + 15 = 30
\]
**Step 2: Calculate the second sum \(\sum_{m=1}^{9}(2m-2)\)**
We can factor out the 2:
\[
\sum_{m=1}^{9}(2m-2) = 2\sum_{m=1}^{9}(m-1) = 2\sum_{m=0}^{8}m = 2\left(\frac{8(8+1)}{2}\right) = 2 \cdot 36 = 72
\]
**Step 3: Multiply the two sums**
Now we multiply the results of the two sums:
\[
30 \cdot 72 = 2160
\]
### Final Result for Problem 4:
\[
\boxed{2160}
\]
---
### Problem 5:
\[
\sum_{s=5}^{11}(7s-4) - 6 \sum_{s=6}^{13}(-3s-2)
\]
**Step 1: Calculate the first sum \(\sum_{s=5}^{11}(7s-4)\)**
Calculating each term:
\[
\begin{align*}
s = 5: & \quad 7(5) - 4 = 35 - 4 = 31 \\
s = 6: & \quad 7(6) - 4 = 42 - 4 = 38 \\
s = 7: & \quad 7(7) - 4 = 49 - 4 = 45 \\
s = 8: & \quad 7(8) - 4 = 56 - 4 = 52 \\
s = 9: & \quad 7(9) - 4 = 63 - 4 = 59 \\
s = 10: & \quad 7(10) - 4 = 70 - 4 = 66 \\
s = 11: & \quad 7(11) - 4 = 77 - 4 = 73 \\
\end{align*}
\]
Now, summing these results:
\[
31 + 38 + 45 + 52 + 59 + 66 + 73 = 364
\]
**Step 2: Calculate the second sum \(\sum_{s=6}^{13}(-3s-2)\)**
Calculating each term:
\[
\begin{align*}
s = 6: & \quad -3(6) - 2 = -18 - 2 = -20 \\
s = 7: & \quad -3(7) - 2 = -21 - 2 = -23 \\
s = 8: & \quad -3(8) - 2 = -24 - 2 = -26 \\
s = 9: & \quad -3(9) - 2 = -27 - 2 = -29 \\
s = 10: & \quad -3(10) - 2 = -30 - 2 = -32 \\
s = 11: & \quad -3(11) - 2 = -33 - 2 = -35 \\
s = 12: & \quad -
Quick Answer
Problem 4: \( 2160 \)
Problem 5: \( 364 \)
Answered by UpStudy AI and reviewed by a Professional Tutor
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