Question

find the domain of the rational function.

f(y)= y+7 / y^2-7y

how would I write it in interval notation?

HELP!

Answer 1

Did you factor the denominator?

Answer 2

The domain is the set of independent variable values (in this case y) that can be plugged into the function to give a valid solution. Follow @Mertsj's thoughtline..

Answer 3

no, i didnt.. let me do that now.

Answer 4

Just remember that the denominator cannot be 0.

Answer 5

If square roots "don't like" negatives inside them, rationals are less picky... they only require that the denominator is not zero....

Answer 6

So whatever number(s) cause the denominator to be 0 must be excluded from the domain.,

Answer 7

y( y - 7)

Answer 8

^yup... now what values of y would make that zero?

Answer 9

Yes. So set each factor equal to 0 and solve those two equations.

Answer 10

i get y = 0 and y = 7

Answer 11

Those are the numbers that must be excluded. All other real numbers are fine replacements for x.

Answer 12

Can you put that information into interval notation?

Answer 13

I dont know how too. lol :/
thats the thing.

Answer 14

I get the work right but I just dont know how to put it in the notation form.

Answer 15

\[(-\infty. 0) U (0,7) U (7,\infty)\]

Answer 16

Ha!!! I had it right!!

Answer 17

Thank you so much!!!!

Answer 18

yw