Rearrange an equation

[Markus123]

Hey, so I'm trying to rearrange a very simple equation but can't seem to get it right. The equation is y = a / sqrt(4x - b), making x the subject. I have attached an image with the steps that I went through and the eventual answer, but it appears to be incorrect. If anyone can tell me what I am doing wrong it will be greatly appreciated.

 

[Deleted member 4993]

Hey, so I'm trying to rearrange a very simple equation but can't seem to get it right. The equation is y = a / sqrt(4x - b), making x the subject. I have attached an image with the steps that I went through and the eventual answer, but it appears to be incorrect. If anyone can tell me what I am doing wrong it will be greatly appreciated.

View attachment 32908

Everything is CORRECT, except on the last line, where you are dividing by 4, you HAVE to divide 'b' by 4 too.

 

[Steven G]

You can't divide the whole right side by 4 and only part of the left side by 4.

For example, 20 + 8 = 28. Now 20/4 + 8 ≠ 28/4, ie 5+8 ≠ 7