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Mathematics 20 Online
OpenStudy (voltron21):

evaluate the limit lim X->9 (x-9)/(x^2-81)

ganeshie8 (ganeshie8):

hint : x^2-81 = x^2-9^2

ganeshie8 (ganeshie8):

hint2 : a^2-b^2 = (a+b)(a-b)

OpenStudy (voltron21):

yea i got that far

ganeshie8 (ganeshie8):

good, apply them

OpenStudy (voltron21):

i did and i canceled x-9 from the top and bottom and plugged 9+9 but apparently 18 isnt the answer what am i doing wrong

ganeshie8 (ganeshie8):

u did a simple mistake, let me show u :)

ganeshie8 (ganeshie8):

\(\large\lim_{ x->9} \frac{(x-9)}{(x^2-81)}\)

ganeshie8 (ganeshie8):

\(\large\lim_{ x->9} \frac{(x-9)}{(x+9)(x-9)}\)

ganeshie8 (ganeshie8):

\(\large\lim_{ x->9} \frac{\cancel{(x-9)}}{(x+9)\cancel{(x-9)}}\)

ganeshie8 (ganeshie8):

\(\large\lim_{ x->9} \frac{1}{(x+9)}\)

ganeshie8 (ganeshie8):

now sub, wat do u get ?

OpenStudy (voltron21):

oh i get it thanks so much i was about to go insane

ganeshie8 (ganeshie8):

np you're wlcme :)

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