## bobbya 2 years ago The variables x and y vary inversely. Which equation relates x and y when x = -1 and y = -9?

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1. AccessDenied

An inverse relation means one variable is the other's reciprocal, at least up to some constant coefficient. $$\displaystyle xy = k$$ <=> $$\displaystyle x = \frac{k}{y}$$ There are three unknowns here, but we are only really interested in that constant k. If we want to find k, we just have to plug in the information we know already and evaluate.

2. bobbya

which on of theses makes sense A. x = y 9 B. y = -9x C. x = 9y D. y = 9

3. AccessDenied

Sorry, I can't read those answers. Could you write them in the "Draw" window?

4. AccessDenied

However, once you know the value of k, it should become obvious by changing k for whatever your constant is. You are given enough information to determine k with the (x = -1, y = -9) just by plugging in the values and evaluating. If you plug them into the equation, you'll have only one variable, which is easily solved for.