Question

Can somebody explain how my online math course got from (x-y)y/(y-x)x to -y/x?

Answer 1

\[xy-y^2/xy-x^2\]

Answer 2

?

Answer 3

Notice that -(x-y) = -x+y = y-x. So, to swap the order like that, we can factor out a -1. Then
\[ \frac{(x-y)y}{(y-x)x} = \frac{-(y-x)y}{(y-x)x} = \frac{-y}{x}\]
after we cancel the (y-x) on the top and bottom.

Answer 4

i'm confused..

Answer 5

did'nt you just multiply the numerator by negative 1?

Answer 6

oh, wait..I got it now...

Answer 7

how do I give you a medal again?

Answer 8

Glad to help! I think you just click that "Good Answer" button.

Answer 9

I don't see the 'good answer' button..

Answer 10

It's usually next to everyone else's post, on the right. Don't worry about it if it's not there.

Answer 11

I gave it for you...

Answer 12

Thanks :)