Question

Evaluate the limit, if it exists. (If an answer does not exist, enter DNE.)
lim
h → 0
((−9 + h)2 − 81)/h

Answer 1

Have you considered expanding the square and simplifying the numerator?

Answer 2

Yes. I get -18+x over x

Answer 3

plugging in zero would make it DNE ?

Answer 4

1) "Plug in" doesn't mean anything. Never do that.
2) Where did 'x' come from?
3) Try again.

(−9 + h)2 − 81
81 - 18h + h^2 - 81
h^2 - 18h

Now, put the fraction back together and see if anything magical happens.

Answer 5

h^2-18h over h^2

Answer 6

Can I simply more?

Answer 7

just over \(h\) dear
then divide

Answer 8

\[\frac{h^2-18h}{h}\] factor the \(h\) out of the numerator and cancel, or else divide each term by \(h\)
same thing
THEN plug in 0 for \(h\)

Answer 9

i get h-18

Answer 10

-18 is the limit?

Answer 11

NOW what happens as h disappears?

Answer 12

yes

Answer 13

thanks