Question

If y varies inversely with x and y= -18 when x = 6 , find y when x=5

Answer 1

Problem:

• if y varies inversely with x and y.= -18 when x = 6, find y when x = 5?

Answer:

• 
  `\huge \: \boxed{y = - 21.6}`

Formula:

• 
  `\boxed{y = (k)/(x) }`

To find k use the given condition:

Given that:

• 
  `y = -18`
• 
  `x = 6`

Lets try!

• 
  `\:y = (k)/(x) \: \: ➡ \: \: \boxed{ k \ = yx}`
• 
  `yx = - 18 * 6 = \boxed{- 108}`

Equation is:

• 
  `\boxed{y = {( - 108)/( \: x)}}`

When x = 5 then,

• 
  `\huge{y = ( - 108)/( \: 5)}`
• 
  `\huge\boxed{y = - 21.6}`

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#LetsStudy

Answer 2

y = -108/5

Explanation:

An inverse variation is xy = k where k is a constant

xy =k

6*-18 = k

-108 = k

xy = -108

Let x = 5

5y = -108

Divide by 5

y = -108/5