Question

y varies inversely as twice x. When x = 3, y = 6. Find y when x = 2.

y = 3

y = 6

y = 9

y = 12

Answer 1

@marissalovescats Nooooo, don;t answer it yet.

Answer 2

Okay... I was just going to give her the equation for inverse variation.

Answer 3

Okay, let's do it @marissalovescats

Answer 4

Well... It's y=k/x.... I think haha. I can't remember everything.

So you plug in y and x to find K then use the k you get and the next x given to fond y.

Answer 5

okay can you walk me through it cause i'm new at this stuff.

Answer 6

Is that the inverse variation equation?

Or is it y=kx? Lol

Answer 7

y = k/x^n

Answer 8

It's y=kx cuz I get an answer that's actually an answer.

There are no exponents in inverse variation I know that for sure @primeralph

Answer 9

Inverse variation? That's k/x^n

Answer 10

I don't remember the equation but I aced Algebra 2 and I really dont think theres an exponent.

Direct variation is y=kx

Inverse= xy=k or y=k/x

Joint= z=kxy..

Answer 11

Since, y varies inversely as twice x
therefore
\[y \alpha \frac{1}{2x} \]
i.e.
\[y =k \frac{1}{2x} \rightarrow y =\frac{K}{2x}\]
Where K is any constant.
Now at x = 3, y = 6, K=?
\[y =\frac{K}{2x} \rightarrow 6 =\frac{K}{2\times3} \rightarrow K=36\]
Thus our eq of Variation becomes
\[ y =\frac{36}{2x} \rightarrow y =\frac{18}{x}\]
Now at x=2 y=?
\[ y =\frac{18}{x} \rightarrow y =\frac{18}{2} \rightarrow y=9\]

Answer 12

Thus y = 9 is the correct answer.

Answer 13

@marissalovescats When you do more math, you'll begin to see the n.