we know all it's doing is adding 6 over again to each term to get the next one, so then
now for the explicit one
![\bf n^{th}\textit{ term of an arithmetic sequence} \\\\ a_n=a_1+(n-1)d\qquad \begin{cases} n=n^{th}\ term\\ a_1=\textit{first term's value}\\ d=\textit{common difference}\\[-0.5em] \hrulefill\\ a_1=7\\ d=6 \end{cases} \\\\\\ a_n=7+(n-1)6\implies a_n=7+6n-6\implies \stackrel{\textit{Explicit Formula}}{\stackrel{f(n)}{a_n}=6n+1} \\\\\\ therefore\qquad \qquad f(10)=6(10)+1\implies f(10)=61](https://tex.z-dn.net/?f=%5Cbf%20n%5E%7Bth%7D%5Ctextit%7B%20term%20of%20an%20arithmetic%20sequence%7D%20%5C%5C%5C%5C%20a_n%3Da_1%2B%28n-1%29d%5Cqquad%20%5Cbegin%7Bcases%7D%20n%3Dn%5E%7Bth%7D%5C%20term%5C%5C%20a_1%3D%5Ctextit%7Bfirst%20term%27s%20value%7D%5C%5C%20d%3D%5Ctextit%7Bcommon%20difference%7D%5C%5C%5B-0.5em%5D%20%5Chrulefill%5C%5C%20a_1%3D7%5C%5C%20d%3D6%20%5Cend%7Bcases%7D%20%5C%5C%5C%5C%5C%5C%20a_n%3D7%2B%28n-1%296%5Cimplies%20a_n%3D7%2B6n-6%5Cimplies%20%5Cstackrel%7B%5Ctextit%7BExplicit%20Formula%7D%7D%7B%5Cstackrel%7Bf%28n%29%7D%7Ba_n%7D%3D6n%2B1%7D%20%5C%5C%5C%5C%5C%5C%20therefore%5Cqquad%20%5Cqquad%20f%2810%29%3D6%2810%29%2B1%5Cimplies%20f%2810%29%3D61)
Let the slower train's velocity be x-21
Let the faster train's velocity be x
We know that the approach speed is the sum of both speeds, so x+x -21= 2x-21.
The approach rate is given by Distance/time = 471/3 = 157mpH
x+x-21=157
2x=157+21
2x=178
x=89mph
The slower train is travelling 89-21 = 68mph
The faster train is travelling 89mph.
Answer:
Step-by-step explanation:
Comment
The one you can pick out that is true is D. The others you have to be careful with. C is a line and it has two arrowheads in the symbol above the two letters which makes it correct as well. A is not correctly marked, so it is not there the way it is marked. One would think ZX is a ray the way it is marked.
Answer: C and D
Answer:
4/7
Step-by-step explanation:
If the slope of line d is -7/4, then the slope of a perpendicular is 4/7.
Given a slope, to find the slope of a perpendicular, flip the fraction and change the sign.
Flip -7/4 to get -4/7. Then change the sign of -4/7 to get 4/7.
Answer: 4/7
I'm going to have to say C.
