Question

find the domain of this function:

h(x)=7/x^2-8x-20

Answer 1

Find what number(s) make the denominator zero and exclude them from the domain.

Answer 2

im confused

Answer 3

Ok.. Division by zero is not allowed because its undefined.

Answer 4

So we need to see if any real numbers make the denominator zero. So to do that you do this \[x^2 - 8x - 20 = 0\] What do you get when you facor this?

Answer 5

wouldnt it be 2 and 10

Answer 6

(x-10)(x+2)

Answer 7

so x would equal 10 and -2

Answer 8

so is that the domains 10 and -2

Answer 9

So the domain would be \[\left\{ x: x \ne 10 \space and \space x \ne -2 \right\}\]

Answer 10

what about the 7 for the numerator its not included

Answer 11

No the numerator can be 0 but the denominator cannot.

Answer 12

Well the numerator will never be 0 so we dont have to worry about it.

Answer 13

oh ok so we dont do nothing with the 7?

Answer 14

Nothing with the 7 :)

Answer 15

oh ok awesome i hae more problems on the way lol

Answer 16

lol ok