#### bumblebee123

##### Junior Member

- Joined
- Jan 3, 2018

- Messages
- 200

Doing Direct and inverse proportion still. Got the hang of it until I saw this question: ( I have used ^ show a square)

Y is directly proportional to x^2. When x=2, y=36

Y is directly proportional to x^2. When x=2, y=36

A)

Express

*y*in terms of

*x*

The answer here is y=9x^2

I got the answer correct but the next bit beats me, I do not know where to begin.

The answer here is y=9x^2

I got the answer correct but the next bit beats me, I do not know where to begin.

**z in inversely proportional to x. When x = 3, z= 2**

B)

Show that

*z*=

*cy^n*, where

*c*and

*c*are numbers and

*c >*

*0*. (you must find the values c and n)

*So, I have managed to find the formula z=6/x but I do not know how to find c or n. I thought about using answer to A for the y value but this doesn't help me. It's probably staring me in the face but I just don't see it.*

I could use the answer I got for z and insert this into the z=cy^n to read:

6/x = cy^n

but I don't see how that will get me answers.

If it helps the answer book says c=18 and n = -1/2

Thank you in advance.