Okay, I've got this question and I've spent about an hour trying to figure it out and it's doing my head in:

Write a formula for the nth term of this quadratic sequence:

7, 15, 27, 43, 63

nth term = ??

Write this expression in completed square form:

x² - 10x +2

Hence solve

x² - 10x +2 = -5

Ok, any help would be appreciated as I've tried many ways of doing it....

Thanks =D