Question

Please please please help ​

Answer 1

see explanation

Explanation:

Given y varies inversely with x then the equation relating them is

y =
`(k)/(x)` ← k is the constant of variation

(1)

To find k use the condition x = 5, y = 10, thus

k = yx = 10 × 5 = 50

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(2)

y =
`(k)/(x)`

To find k use the condition y = 8, x = 10

k = yx = 8 × 10 = 80

y =
`(80)/(x)` ← equation of variation

when y = 4, then

4 =
`(80)/(x)` ( multiply both sides by x )

4x = 80 ( divide both sides by 4 )

x = 20

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(3)

y =
`(k)/(x)`

To find k use the condition y = - 5, x = 20

k = yx = - 5 × 20 = - 100

y =
`(-100)/(x)` ← equation of variation

when y = - 4, then

- 4 =
`(-100)/(x)` ( multiply both sides by x )

- 4x = - 100 ( divide both sides by - 4 )

x = 25