we know that a₁ = 1, and aₙ = aₙ₋₁ + 2, is another way of saying, we add 2 to get the next term, namely, 2 is the common difference.
![\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=1\\ d=2\\ n=7 \end{cases} \\\\\\ a_7=1+(7-1)2\implies a_7=1+12\implies a_7=13](https://tex.z-dn.net/?f=%5Cbf%20n%5E%7Bth%7D%5Ctextit%7B%20term%20of%20an%20arithmetic%20sequence%7D%0A%5C%5C%5C%5C%0Aa_n%3Da_1%2B%28n-1%29d%5Cqquad%0A%5Cbegin%7Bcases%7D%0An%3Dn%5E%7Bth%7D%5C%20term%5C%5C%0Aa_1%3D%5Ctextit%7Bfirst%20term%27s%20value%7D%5C%5C%0Ad%3D%5Ctextit%7Bcommon%20difference%7D%5C%5C%5B-0.5em%5D%0A%5Chrulefill%5C%5C%0Aa_1%3D1%5C%5C%0Ad%3D2%5C%5C%0An%3D7%0A%5Cend%7Bcases%7D%0A%5C%5C%5C%5C%5C%5C%0Aa_7%3D1%2B%287-1%292%5Cimplies%20a_7%3D1%2B12%5Cimplies%20a_7%3D13)
2(2)2(3)2(4)=192 because you're multiplying everything together in order to find your answer and also because the variables which are the letters represent the numbers that need to be multiplied idk if that made sense but that's the answer lol
7/8*8/9 = (7*8)/(8*9)
Since we have an 8 both above and below, we can erase it, and so the answer is 7/9
Cube has 6 faces/planes :)