+0

let x#y=(x^2)/y for all values of x and y where y does not equal 0. Find all values of x such that x#3=9. Thanks so much!

0
159
1
+272

let x#y=(x^2)/y for all values of x and y where y does not equal 0.  Find all values of x such that x#3=9.  Thanks so much!

WhichWitchIsWhich  Nov 3, 2017
#1
+16
+2

So a function (?) question.  Also, it doesn't specify whether it should be an integer or not.  I'm guessing you mean an integer.

We are told that $$x = x$$ and $$y=3$$.  Plug it in.

$$x$$#$$3$$$$=\dfrac{x^2}{3}$$

Also, $$x$$#$$3=9$$.  Plug that in too.

$$9= \dfrac{x^2}{3}$$ .  Now multiply both sides by 3 to get rid of the fraction...

$$27=x^2$$.  So $$x = \sqrt{27}$$.  It is also equal to $$- \sqrt{27}$$.  THAT DOES NOT LOOK LIKE A NICE NUMBER.

Unless I made a mistake which is 100% possible.

Vivien  Nov 4, 2017
edited by Vivien  Nov 4, 2017