Answer:
28 2/3
Step-by-step explanation:
1 1/4 + 1 2/3 + 25 3/4
5/4 + 5/3 + 103/4
15/12 + 20/12 + 309/12
344/12
172/6
86/3
= 28 2/3
Answer:
negative number times negative number gives you positive number.
Step-by-step explanation:
-9x-3
=27
Well you have to go by 24x3 and that equals 72 miles
Step-by-step explanation:
OK. It's an arithmetic sequence:
![a_1=20,\ a_2=18.5,\ a_3=17,\ ...\\\\a_1=20,\ d=-1.5](https://tex.z-dn.net/?f=a_1%3D20%2C%5C%20a_2%3D18.5%2C%5C%20a_3%3D17%2C%5C%20...%5C%5C%5C%5Ca_1%3D20%2C%5C%20d%3D-1.5)
The explicit formula of an arithmetic sequence:
![a_n=a_1+(n-1)d](https://tex.z-dn.net/?f=a_n%3Da_1%2B%28n-1%29d)
Substitute:
![a_n=20+(n-1)(-1.5)=20-1.5n+1.5=21.5-1.5n](https://tex.z-dn.net/?f=a_n%3D20%2B%28n-1%29%28-1.5%29%3D20-1.5n%2B1.5%3D21.5-1.5n)
The sigma notation of the sum of the first ten terms:
![\sum\limits_{n=1}^{10}(21.5-1.5n)](https://tex.z-dn.net/?f=%5Csum%5Climits_%7Bn%3D1%7D%5E%7B10%7D%2821.5-1.5n%29)
What are your mistakes:
![\sum\limits_{n=20}^{6.5}\to\boxed{n=20},\ \boxed{6.5}](https://tex.z-dn.net/?f=%5Csum%5Climits_%7Bn%3D20%7D%5E%7B6.5%7D%5Cto%5Cboxed%7Bn%3D20%7D%2C%5C%20%5Cboxed%7B6.5%7D)
The first ten terms, not from 20th to 29th (you wrote 6.5?)
![\sum\limits_{n=1}^{10} - \text{the sum for n = 1 to n = 10}](https://tex.z-dn.net/?f=%5Csum%5Climits_%7Bn%3D1%7D%5E%7B10%7D%20-%20%5Ctext%7Bthe%20sum%20for%20n%20%3D%201%20to%20n%20%3D%2010%7D)
-2, because it is farther to the right that-3 on the real number line.