Question

xy = –25. What is the constant of variation for this relationship?

Answer 1

@whpalmer4

Answer 2

Is that direct, indirect, or joint variation?

Answer 3

Errr, I dunno

Answer 4

Okay,

Direct variation: \(y = kx\)
Indirect variation: \(y = k/x\) or \(xy = k\)
Joint variation: \(z = kxy\)

Answer 5

Indirect variation

Answer 6

Very good. The constant of variation is?

Answer 7

How do I find that

Answer 8

Very easy. Write down "xy = -25" on a blank piece of paper. Look at the paper. Anything that isn't "x", "y", or "=" is the constant of variation :-)

Answer 9

It's \(k\) in all of the formulas I gave you...

Answer 10

So the constant of variation is -25?

Answer 11

yes

Answer 12

O.O Thats it?

Answer 13

That's it! The key here was recognizing that \(xy=-25\) is the same as \(y = -25/x\)

Answer 14

Thx