Question

y varies indirectly as twice x. When x = 9, y = 2. Find y when x = 3.

Answer 1

From what i understand its saying that every time x gains a value of 1, y gains a value of 2, therefore the slope of the line would be 2
From the given point and the slope we can determine the y-intercept
2 =2(9) + b
2-18 = b
b= -16

Now we have the standard equation of a line
\[y = mx +b\]
We can plug in the x given, the m and the b we found to get your answer

y = 2(3) - 16
y = 6-16
y = -10

Answer 2

There is a formula for indirect variation (aka inverse variation) and that is y = k over x
But since your question says "twice x", it would become y = k over 2x
Find k first by using 9 and 2
Once you have found k, you can now find y when x = 2 by plugging them in again.

Answer 3

2 = k/2(9)
2 = k/18
36 = k

y = 36/2(3)
y = 36/6
y = 6 when x is 3