Question

lim x->16,
x^2-256/(sqrt(x)-4)

Answer 1

first factorize the top into (x+16)(x-16) (difference of squares)
then factorize (x-16) into (sqrt(x)-4)(sqrt(x)+4)
now cancel and substitute x=16
Answer is 256

Answer 2

\[{(x^2-256)(\sqrt{x}+4) \over (\sqrt{x}-4)(\sqrt{x}+4)}={(x-16)(x+16)(\sqrt{x}+4) \over x-16}=(x+16)(\sqrt{x}+4)\]
Just plug x=16 and get your answer.

Answer 3

ya thats right ty i did not factor the top first

Answer 4

You're welcome!

Answer 5

how did you know to factor the top first?

Answer 6

Because I knew that it would be cancelled out with the bottom.

Answer 7

haha ok lol i guess i should just do some more

Answer 8

Yeah I guess so :D