# Homework Help: Transformed equation

1. Aug 28, 2011

### footmath

Hello , please guide me .
How can I transformed the equation [TEX]x^{5}-x^{4}-x^{3}-x^{2}-x-1 =0 [/TEX]to [TEX]y^{5}+2y^{2}+47y+122 [/TEX] ?
I studied a lecture that the writer had written :<< by using [TEX]y=x^{2}-3x[/TEX] we can transformed [TEX] x^{5}-x^{4}-x^{3}-x^{2}-x-1 =0[/TEX] to [TEX]y^{5}+2y^{2}+47y+122 [/TEX] But how ? if in [TEX]y=x^2-3x [/TEX] we obtain [TEX]x[/TEX] by [TEX]y[/TEX] we will have : [TEX]x=3/2+\sqrt{y+9/4}[/TEX] and if we substitute [TEX]x=3/2+\sqrt{y+9/4}[/TEX] in [TEX]x^{5}-x^{4}-x^{3}-x^{2}-x-1 =0[/TEX] we don't have $y^5+2y^2+47y+122$ . please explain it.
Thank you very much

2. Aug 28, 2011

### Staff: Mentor

footmath, please edit your post to fix your LaTeX. All of your TEX and /TEX tags need to be written in lower case - as tex and /tex (inside square brackets).