Question

I would greatly appreciate your help loves <3
looking for steps not just answers, will medal.

Simplify and identify the x, y value when the expression is not valid.
9x4y3/(27X6y) =
(x2-16)/(x+4) =
[5x2y/25xy3]÷[x2y/5xy2]
[(x2-25)/(y-3)]÷[(x+5)/(y2-9)]
(3x+y)/(x-1) + (2x+5y)(x-1) =
(3x-5y)/(x+1) – y/(x-1) =

Answer 1

Either i am blind...or there are no question marks...

Answer 2

ok, so what does not valid mean? any ideas?

Answer 3

just refresh your page

Answer 4

ok, so read this then come back and let me know what you think: http://www.purplemath.com/modules/solvrtnl.htm

Answer 5

when x is equal to zero?

Answer 6

close, so the issue is when the bottom of the fraction equals zero, so if you just have an x on the bottom, then yes. x=0 is a singularity(ie the function defies the rules we made for it)

Answer 7

but if you have x-3 on the bottom, when does that =0?

Answer 8

when x is 3?

Answer 9

exactly!

Answer 10

so your goal here is to determine when the bottom equals zero, because then the function is what we call undefined

Answer 11

you may wish to simplify first

Answer 12

ok

Answer 13

so give the first one a try

Answer 14

would it be y^2/3x^2

Answer 15

well, for the simplification yes, so when does that function not exist?

Answer 16

Im not sure

Answer 17

what value makes the bottom =0?

Answer 18

0?