Need Help: (X / 4) ^ 2 * 100 = Y, X = ?

• Jun 18th 2012, 01:50 AM
michaelkamms
Need Help: (X / 4) ^ 2 * 100 = Y, X = ?
Hi,

I have following formula:

(X / 4) ^ 2 * 100 = Y

I would like to find out the value of X, given I have the value of Y:

X = ?

I do not know to to move the power of 2 to the other side...

Thanks
• Jun 18th 2012, 01:52 AM
Prove It
Re: Need Help: (X / 4) ^ 2 * 100 = Y, X = ?
Quote:

Originally Posted by michaelkamms
Hi,

I have following formula:

(X / 4) ^ 2 * 100 = Y

I would like to find out the value of X, given I have the value of Y:

X = ?

I do not know to to move the power of 2 to the other side...

Thanks

To undo a square you have to take a square root.
• Jun 18th 2012, 02:00 AM
michaelkamms
Re: Need Help: (X / 4) ^ 2 * 100 = Y, X = ?
OK, got it, I think should be something like:

(Y / 100)^(1/2) * 4

• Jun 18th 2012, 02:02 AM
Prove It
Re: Need Help: (X / 4) ^ 2 * 100 = Y, X = ?
Quote:

Originally Posted by michaelkamms
OK, got it, I think should be something like:

(Y / 100)^(1/2) * 4

It's actually \displaystyle \displaystyle \begin{align*} \pm 4\sqrt{\frac{y}{100}} \end{align*}.
• Aug 8th 2012, 10:46 PM
manoj9585
Re: Need Help: (X / 4) ^ 2 * 100 = Y, X = ?
Quote:

Originally Posted by michaelkamms
Hi,

I have following formula:

(X / 4) ^ 2 * 100 = Y

I would like to find out the value of X, given I have the value of Y:

X = ?

I do not know to to move the power of 2 to the other side...

Thanks

I think it will be done like this:
(X / 4) ^ 2 = Y/100
X / 4= √(Y/100)
X = 4*√(Y/100)

algebra solver
• Aug 16th 2012, 10:17 PM
manoj9585
Re: Need Help: (X / 4) ^ 2 * 100 = Y, X = ?
Quote:

Originally Posted by cobooboc
I think X=4/√(Y/100) ...

I don't think so , read it properly. it's a minor mistake.
• Aug 17th 2012, 08:03 PM
Wilmer
Re: Need Help: (X / 4) ^ 2 * 100 = Y, X = ?
Quote:

Originally Posted by michaelkamms
(X / 4) ^ 2 * 100 = Y
I would like to find out the value of X, given I have the value of Y:
X = ?

C'mon guys...keep it simple (Wink)

(X / 4) ^ 2 = X^2 / 16
SO:
100X^2 / 16 = Y
X^2 = 16Y / 100
X^2 = 4Y / 25
X = +-2SQRT(Y) / 5
• Aug 20th 2012, 07:44 AM
Re: Need Help: (X / 4) ^ 2 * 100 = Y, X = ?
Indeed. Don't forget that if $\displaystyle x^2=a$, then $\displaystyle x=\pm\sqrt{a}$, not simply $\displaystyle \sqrt{a}$.
• Sep 2nd 2012, 11:47 PM
kalwin
Re: Need Help: (X / 4) ^ 2 * 100 = Y, X = ?
(x+y)^4 - 100(x+y)^2

(x+y)² ((x+y)² -100)
• Sep 3rd 2012, 02:39 AM
Prove It
Re: Need Help: (X / 4) ^ 2 * 100 = Y, X = ?
Quote:

Originally Posted by kalwin
(x+y)^4 - 100(x+y)^2

(x+y)² ((x+y)² -100)

Assuming you are trying to factorise this, you are on the right track. Now make use of the Difference Of Two Squares rule: \displaystyle \displaystyle \begin{align*} a^2 - b^2 = (a - b)(a + b) \end{align*}.