Question

Simplify the rational expression.

(45y-9xy)/(x^2y-25y)


I got an answer of 9y/y(x+5) but it seems to be wrong. Can anyone solve this for me and see what they get? Thank you

Answer 1

First take out obvious common factors
(45y-9xy)/(x^2y-25y)
=9y(5-9x)/y(x²-25)

cancel out the common factor y from the numerator and denominator and see if there are other factoring you can do.

Answer 2

I did that u get 9y(5-9x)/((x-5)(x+5)) but it is still wrong

Answer 3

Did you leave the "y" in the numerator?

Answer 4

sorry what I was suppose to write was 9y(5-9x)/y((x-5)(x+5))

do you see where there is still a mistake?

Answer 5

If you have a "y" both in the numerator and denominator, you can cancel them out as long as y≠0.

For example:
5y(x-1)/(25xy²)
=5y(x-1)/(5y(5xy)) ... here, remove 5y, a common factor
=(x-1)/(5xy)

Answer 6

so will the final answer be 9(5-9x)/((x-5)(x+5)) ?

Answer 7

Correct!

Answer 8

It still shows me as wrong when I submit online

Answer 9

Sorry, there was a mistake in:
(45y-9xy)/(x^2y-25y)
=9y(5-9x)/y(x²-25)

Should have read:
(45y-9xy)/(x^2y-25y)
=9y(5-x)/y(x²-25)

Now can you figure out the answer and try again?