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?

1 Answer
Don't Memorise
Jun 10, 2015
  1. xy = color(red)(-17.6xy=−17.6
  2. color(blue)( y = -2.75y=−2.75

Explanation:

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

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

So color(red)(k) = 3.2 xx (-5.5)k=3.2×(−5.5)

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

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

color(blue)(y) =k/xy=kx
color(blue)(y =-17.6/6.4 = -2.75y=−17.66.4=−2.75

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