Question

If y varies inversely as x2 and y=6 when x=30, what is y when x=6

Answer 1

y= 150

Explanation:

`y\ \alpha \ (1)/(x^2)\\\\y = k * (1)/(x^2)\\\\`

Given y = 6, and x = 30. Find k.

`6 = k * (1)/(30^2)\\\\6 * 900 = k\\\\5400 = k`

Given x = 6 and k = 180. Find y

`y = 5400* (1)/(6^2)\\\\`

`=5400 * (1)/(36)\\\\=150`

Answer 2

y = 150

Explanation:

y varies inversely as x²

yx² = k

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y = 6 when x = 30

6(30²) = k

6(900) = 5400

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what is y when x = 6

y(6²) = 5400

y(36) = 5400

y = 5400/36

y = 150