Is there a picture to go with it?
The pattern is:
( a - b )² = a² - 2 a b + b² ( square of last term of binomial - the missing term)
x² - 2 · 8 · x + 8² = x² - 16 x + 64 = ( x - 8 )²
The missing term is: 64
Given the recursive formula, each terms is five time the previous one.
This means that:
is 5 times
, which means 
- in turn,
is 5 times
, so we have
. This means that 
- Finally,
So, substituting this back gives

In general, since you have
, each time you compute a new term you multiply by a factor of 5, so if
, you have

3(k-x)= -3x-9
3k - 3x = -3x - 9 ← equation without parentheses
3k - 3x + 3x = - 9
3k = -9
k = -9/3
k = -3 ← simplest form
Answer:
2x²√13
Step-by-step explanation:
√52x⁴ = √4×13×x⁴ = 2x²√13