Next 6 terms =81 ,243,729,2187,6561,19683
Please add a photo so we can understand what you mean and your question.
8/7 exact form
or
1 1/7 mixed number form
You plug in -3 for x for 4(-3)+5 =-7
A^2-2ab+b^2=(a-b)^2
(a-b)^2- c^2= (a-b-c)(a-b+c)
[difference of square]
Hope this can help.