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If y varies inversely as x and y = 12 when x = 3, how do you find x when y = 18?

Answer 1

Eli Assouline

To find x when y = 18, we can use the inverse variation formula: y = k/x.

First, we need to find the value of k, which is the constant of variation.

Given that y = 12 when x = 3, we can substitute these values into the formula: 12 = k/3.

To solve for k, we can multiply both sides of the equation by 3: 36 = k.

Now that we know the value of k, we can substitute it into the formula: 18 = 36/x.

To solve for x, we can multiply both sides of the equation by x: 18x = 36.

Finally, we divide both sides of the equation by 18 to isolate x: x = 2.

Therefore, when y = 18, x = 2.

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Answer 2

Nathan Axel

#x=2#

As #y# varies inversely as #x#, #yprop1/x# or #y=kxx1/x#

i.e. #x xxy=k#

Hence as when x=3#, #y=12#, we have

#k=3xx12=36#

and therefore when #y=18#

we have #x xx18=36#

or #x=36/18=2#

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Answer from HIX Tutor

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