Question

How do you write an inverse variation equation that relates x and y when you assume that y varies inversely as x given that if y=3.2 when x= -5.5, find y when x= 6.4?

Answer 1

1. `xy = color(red)(-17.6`
2. `color(blue)( y = -2.75`

Explanation:

`color(blue)(xy) =color(red)(k` is the representation of inverse variation.

• Inverse variation 1
  `y =3.2`
  `x = -5.5`

So `color(red)(k) = 3.2 xx (-5.5)`

`color(red)(k =- 17.6`
So the variation can be mentioned as `xy = color(red)(-17.6`

• Inverse variation 2
  Now we have the value of the constant
  `color(red)(k=-17.6`
  And as per the question
  `x=6.4`

`color(blue)(y) =k/x`
`color(blue)(y =-17.6/6.4 = -2.75`