Question

If a/x-b/y=c and xy= 1/c, then bx=
A) 1-ay B) ay C) ay+1 D) ay-1or E) 2ay ?

Answer 1

D) ay-1

Answer 2

Why?

Answer 3

Add the first 2 terms to get an xy on the bottom and sub in 1/c for it.

Answer 4

That's what i did but i get B as the answer which is not correct.

Answer 5

U did it wrong, u should get

(ay - bx) /xy = c as first step.

Answer 6

This is how I did it:

If xy = 1/c, then c = 1/xy
If a/x - b/y = c, a/x - b/y = 1/xy
Multiply a/x - b/y = 1/xy, by it's LCD which is xy
This gives you ay - bx = 1
Add bx to both sides, subtract 1 from both sides.
ay -1 = bx or bx = ay -1

Answer 7

Oh ok tysm for explaining.

Answer 8

(ay - bx) /xy = c ->

(ay - bx) = c * 1/c = 1 ->

bx = 1 - ay