I made a number line and drew it out -6,-5,-4,-3,-2,-1,0,1,2 and i counted how many i had to move over to get to 2 from -6 and i got 8
Answer:
![S_{31}=71.3](https://tex.z-dn.net/?f=S_%7B31%7D%3D71.3)
Step-by-step explanation:
The nth term of an arithmetic sequence is given by the formula,
![U_n=a_1+(n-1)d](https://tex.z-dn.net/?f=U_n%3Da_1%2B%28n-1%29d)
We were given that the 9th term is
.
![\Rightarrow 17=a_1+(9-1)(-2.1)](https://tex.z-dn.net/?f=%5CRightarrow%2017%3Da_1%2B%289-1%29%28-2.1%29)
![\Rightarrow 17=a_1+(8)\times(-2.1)](https://tex.z-dn.net/?f=%5CRightarrow%2017%3Da_1%2B%288%29%5Ctimes%28-2.1%29)
![\Rightarrow 17=a_1-\frac{84}{5}](https://tex.z-dn.net/?f=%5CRightarrow%2017%3Da_1-%5Cfrac%7B84%7D%7B5%7D)
![\Rightarrow 17+\frac{84}{5}=a_1](https://tex.z-dn.net/?f=%5CRightarrow%2017%2B%5Cfrac%7B84%7D%7B5%7D%3Da_1)
![\Rightarrow a_1=\frac{169}{5}](https://tex.z-dn.net/?f=%5CRightarrow%20a_1%3D%5Cfrac%7B169%7D%7B5%7D)
The sum of the first n-terms is given by the formula,
![S_n=\frac{n}{2}(2a_1+(n-1)d)](https://tex.z-dn.net/?f=S_n%3D%5Cfrac%7Bn%7D%7B2%7D%282a_1%2B%28n-1%29d%29)
To find
, we substitute
,
and
.
![\Rightarrow S_{31}=\frac{31}{2}(2(\frac{169}{5}+(31-1)(-2.1))](https://tex.z-dn.net/?f=%5CRightarrow%20S_%7B31%7D%3D%5Cfrac%7B31%7D%7B2%7D%282%28%5Cfrac%7B169%7D%7B5%7D%2B%2831-1%29%28-2.1%29%29)
![\Rightarrow S_{31}=\frac{31}{2}(2(\frac{169}{5}+(30)(-2.1))](https://tex.z-dn.net/?f=%5CRightarrow%20S_%7B31%7D%3D%5Cfrac%7B31%7D%7B2%7D%282%28%5Cfrac%7B169%7D%7B5%7D%2B%2830%29%28-2.1%29%29)
![\Rightarrow S_{31}=\frac{31}{2}(\frac{23}{5})](https://tex.z-dn.net/?f=%5CRightarrow%20S_%7B31%7D%3D%5Cfrac%7B31%7D%7B2%7D%28%5Cfrac%7B23%7D%7B5%7D%29)
![\Rightarrow S_{31}=\frac{713}{10}](https://tex.z-dn.net/?f=%5CRightarrow%20S_%7B31%7D%3D%5Cfrac%7B713%7D%7B10%7D)
![\Rightarrow S_{31}=71.3](https://tex.z-dn.net/?f=%5CRightarrow%20S_%7B31%7D%3D71.3)
The correct answer is D
Answer:
1,128
Step-by-step explanation:
94 x 12 = 1,128
what hy7h7yh
Answer: x=4
Step-by-step explanation:
firstly you solve the barracks first by multipy 2 into ( x+8) after that you collect like terms on one side of the equation or make x become the subject of the equation and solve for x